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Thread Title:

CRUISE NOIT WORKING ON 1993 FLD120 WITH DDECII

Created On Friday January 01, 2010 16:12

henboy1

Posts: 37
Joined: Jan 2010

Friday January 01, 2010 16:12

My cruise control has always worked until I had TA change my in-dash valve(red and yellow valve).I was going down the road and when I activated the cruise I was getting nothing.I then drove to another TA and they diagnosed the problem as being the Clutch switch and claimed it was nothing they did becasue the cruise toggle switch was no where near where they worked(in-dash valve).
After leaving the second TA and being charged a 2nd time for diags, I decided to fix it myself.What the guy at the 2nd TA showed me was the idle-up and which he thought made the cruise work.He held down the clutch and bumped the cruidse to keep the idle up, and this worked.He immediately said my Clutch switch was acting up.
After doing a few test myself, When you depress the clutch and bump the idle with the cruise, the idle -up works but not the cruise when going doiwn the road.I was able to play with the clutch switch wires(reverse them) to activate the idle-up without having to depress the clutch switch.Even though I can now idle high, the cruise will still not work on the road.

I then took off the in dash panel and around where the valves are located.I just couldn't see any unplugged wire.I then called the dealer to find out if their schematic shows any switch behind the in-dash valve relating to the cruise.They did claim there are two switches behind there and that one is normally "open" and the other is "closed".They adviced that TA probably reversed the switch when putting everything back together.I had time to play with some in dash switches today to see if the cruise will work. Have I mesed up the wiring by tampering with the clutch switch to make the idle-up work?
In my opinion, the clutch switch and the cruise toggle is not dependent on each other but I might be wrong.What do I need to check or how can I go about checking for current because I see no RELAY FOR THE CRUISE UNDER THE DASH PANEL.

-------------------------
Independent trucker
Stockbridge, Georgia

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stump

Posts: 814
Joined: Aug 2007

Friday January 01, 2010 17:16
Here is a link to the DDEC2 wiring diagram it should help you out. Look and follow wire 543 I think you will find the problem somewhere on this circuit. http://supermiller.com/pdf/SK20627.pdf Edited: Friday January 01, 2010 at 17:27 by stump

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GoneFishen

Posts: 1325
Joined: Jan 2007

Friday January 01, 2010 18:33

When you are parked the parking brake switch sends a signal to the computer telling it that the brakes are applied. SO when you release the parking brake the computer thinks you are driving. What happens is sometimes the air switch is faulty and the computer still thinks you are parked but you are moving. This cofuses the computer so the cruise does not work. Yes it is possible the clutch switch is also faulty. Use a scan tool to actually see what switches are applied when the air brakes are applied and not applied. The scan tool also can see if the clutch switch works and the cruise switches as well.

-------------------------
DDA tech for 30 years,all 2 cycle,series 60,50 mbe also.
1995 F250, 191k mi.
Lost Wages, Nv

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henboy1

Posts: 37
Joined: Jan 2010

Saturday January 02, 2010 02:16

<< When you are parked the parking brake switch sends a signal to the computer telling it that the brakes are applied. SO when you release the parking brake the computer thinks you are driving. What happens is sometimes the air switch is faulty and the computer still thinks you are parked but you are moving. This cofuses the computer so the cruise does not work. Yes it is possible the clutch switch is also faulty. Use a scan tool to actually see what switches are applied when the air brakes are applied and not applied. The scan tool also can see if the clutch switch works and the cruise switches as well. >>

I forgot to mention something, I do see 2-3 connections that have been unplugged.Their connections are both females(black plastic) and they defineitely cannot go into each other unless TA dropped a pitail connection that makes them connect to each other.For testing purposes, I joined two of the leads (3 wires going into 1 black female conector)with a jumper cable and when the truck was still off the fuel gauge immediately fell much lower than if I had no fuel.This makes me think these connectors may not be part of the 543 circuit.I never used my electronics schooling and therefore have NO CONFIDENCE IN IT.What is the scan tool like?Is it the one with a pointy edge that checks for connectivity and current?How much?
Thanks!

-------------------------
Independent trucker
Stockbridge, Georgia

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henboy1

Posts: 37
Joined: Jan 2010

Saturday January 02, 2010 02:38

<< Here is a link to the DDEC2 wiring diagram it should help you out. Look and follow wire 543 I think you will find the problem somewhere on this circuit.

http://supermiller.com/pdf/SK20627.pdf >>

1 more bothersome post.I am looking at the schematic and there is no mention of a relay at the back of my cover but there seem to be a relay for the cruise in this schematic.Around 439, there seem to be a relay noted as "CRUISE LIGHT RELAY".I am confused because I have no light for the relay, just 2 toggle switches.If I can at least find a bad relay, and I believe this is where I need to start before buying a probe.
If I can't do it today, it goes to the shop.

-------------------------
Independent trucker
Stockbridge, Georgia

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stump

Posts: 814
Joined: Aug 2007

Saturday January 02, 2010 05:55
Are you sure you have a DDEC2 system. Here is a DDEC3 diagram it shows 2 switches on the cruise. Look at your ECM on the side of the engine do all the wires come out the same end DDEC2 If wires come out both ends DDEC3 http://supermiller.com/pdf/sk25038.pdf

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GoneFishen

Posts: 1325
Joined: Jan 2007

Sunday January 03, 2010 10:54

The cruise light was objectional to he drivers because they are not used to a constant blue light on the dash. This feature was eliminated. Sometimes by a piece of black electrical tape covering the light. On/off, set/resume. The reader I own is the DDR, company has laptops for use so I just use that program. [DDDL].

-------------------------
DDA tech for 30 years,all 2 cycle,series 60,50 mbe also.
1995 F250, 191k mi.
Lost Wages, Nv

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henboy1

Posts: 37
Joined: Jan 2010

Sunday January 03, 2010 18:04

I have pretty much given up today on tinkering with this thing.
Although I forgot to check my ECM mounted on the side of the frame in the engine bay, I was able to do all kind of test.I am sure since I have a 1993 FLD the engine will definetly be a DDECII.

I was able to totally remove and disconnect the clutch switch today.I jumped the wires on top of each other, one at a time.My current tester did show one having current as the toggle for the cruise was ON.The other two was listed as normal etc... and common.This made no difference and I was also able to reverse every switch attached to the MP3(in-dash valve).
Since I am quite technically challenged to use a scanner and schematic, I am giving up and taking it to the mech.The question is............what the heck could TA have done to screw up my cruise

-------------------------
Independent trucker
Stockbridge, Georgia

Edited: Sunday January 03, 2010 at 18:16 by henboy1

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henboy1

Posts: 37
Joined: Jan 2010

Sunday January 03, 2010 18:04
------------------------- Independent trucker Stockbridge, Georgia

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GoneFishen

Posts: 1325
Joined: Jan 2007

Wednesday January 06, 2010 18:52

If I remember there are 2 switchew on that circuit. trucks are different eCH YEAR. They could have: put the wires on a NC circuit not the NO. moved a connector inside the wire loom, put the wrong wires on the switch, any number of things. I hate to go into dashboards, I always screw something up with my big fingers.

-------------------------
DDA tech for 30 years,all 2 cycle,series 60,50 mbe also.
1995 F250, 191k mi.
Lost Wages, Nv

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stonefly

Posts: 286
Joined: Feb 2008

Thursday January 07, 2010 12:59

I've had a couple of pressure switches go bad. They caused an intermittent failure of the cruise control.

In fact, I'm having the problem now. The cruise will quit working for a few days, and then it will work, and then not.

I don't use it as much as I used to so I'm ignoring it when it doesn't work. Then, I'll try it, and it's working again.

I think it's the pressure switch again.

It's difficult to reach. I also have a 1993 FLD 120, so I can assure you that if you change that switch, you'll be wishing you were the size of an elf, or even smaller. It's a difficult place to reach, but you can do it. I did. (but it wasn't easy)

stonefly

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henboy1

Posts: 37
Joined: Jan 2010

Saturday January 09, 2010 01:27
------------------------- Independent trucker Stockbridge, Georgia

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henboy1

Posts: 37
Joined: Jan 2010

Saturday January 09, 2010 02:20

<< I've had a couple of pressure switches go bad. They caused an intermittent failure of the cruise control.

In fact, I'm having the problem now. The cruise will quit working for a few days, and then it will work, and then not.

I don't use it as much as I used to so I'm ignoring it when it doesn't work. Then, I'll try it, and it's working again.

I think it's the pressure switch again.

It's difficult to reach. I also have a 1993 FLD 120, so I can assure you that if you change that switch, you'll be wishing you were the size of an elf, or even smaller. It's a difficult place to reach, but you can do it. I did. (but it wasn't easy)

stonefly >>

I took the truck to my mech. and he was perplexed himself.He also told me to put back the clutch switch that I had unplugged.While the clutch switch was unplugged, he plugged his scanner into the ECM connector under the dash.It was able to read all the cruise control switches.The working switches were all the cruise control toggle switches but not the brake switch in the dash, as the scanner had indicated.That maybe wrong since the clutch switch wasn't connected at that time.I have since then bought a new clutch switch and a new pressure switch that connects behind the MV3.I haven't installed the pressure switch yet but I have unscrewed the one TA installed and I am about to put in the new pressure switch.
I really doubt this will solve it.One thing I noticed is that the pressure switch from TA had bigger thread diameter than the one I bought from freightliner.
Now there are about 4 pressure switches that I know about.There is one right above the brake peddle and on the firewall which actually triggers the buzzer light(I had that go out 2 yrs ago).The second one is right behind the MV3(red and yellow valve).The third is connected directly to the differential locking lever/switch.The fourth is connected on a panel where a bunch of hoses go.
The question is, all these switches look alike and as the dealer mentioned one of those switches is opened and the other is closed and how the heck would one know if you have the RIGHT OPENED/CLOSED PRESSURE SWITCH?I specifically asked freightliner for the switch screwed into the back of the MV3.I will update sunday.

This is unrelated:
STONEFLY, you did mention also having a 1993 FLD120.In 20 degree or lower weather my brake lines are freezing.I called the dealer to find out if I needed a dryer.Come to find out this truck came without one.No wonder I keep pulling on the air tank strings without any hope.Sometimes those strings even freezes.I got stuck one day in MI in about zero degree weather.The shop ran air dryer directly through my pump (outlet lines).Not just that but they used their shop air compressor to flush out the ice in my system.He did claim this will last through out the winter and it

-------------------------
Independent trucker
Stockbridge, Georgia

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henboy1

Posts: 37
Joined: Jan 2010

Saturday January 09, 2010 02:23
Without putting a dryer on this truck how can I slve my freezing problems in the brake system?Pouring air dryer through the glad hands defintely do not work for me. Sorry for the double post.Pulling the strings do not work for me. ------------------------- Independent trucker Stockbridge, Georgia

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stonefly

Posts: 286
Joined: Feb 2008

Saturday January 09, 2010 05:47

It's only now the beginning of winter. This is a good time to get that air dryer. Considering the problems you may run into during a long cold winter, global warming notwithstanding, you'd be money ahead.

I'll relay to you what I know about the air dryer and maybe it will help.

There should be a small air line running from the governor on your air compressor to the wet tank, the tank which receives the air from the output of the compressor. That small line between the wet tank and the governor signals the governor to load or unload the compressor.

If you have an air dryer, you have another line coming out of the governor. That line will go to the air dryer. It carries the pressure required to purge the air dryer.

If you install an air dryer, the output of the compressor will go to the air dryer, and the output of the dryer will go to the wet tank. You're simply placing the air dryer between the compressor and the wet tank.

When the wet tank gets up to pressure, that pressure goes up the small airline to the governor and the governor unloads the compressor. The same pressure that unloads the compressor goes out the other port of the governor, down the small air line to the air dryer, and purges the dryer.

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stonefly

Posts: 286
Joined: Feb 2008

Saturday January 09, 2010 06:00

I wish I could help you further on the switch problem. Yes, there are numerous switches that could be involved, and it's been so many years since I worked on mine that I don't want to give you a bum steer.

I do remember this, though. For a while, I was getting my cruise to kick back into function by waiting until I was clear of other traffic and stamping hard on the brake pedal, not hard enough or long enough to lock the wheels, but enough to jog the switch. It worked for a while.

Then one day I heard an air leak behind the dash. A pressure switch had blown out. A lot of good my stomping did. It only proves that there are right ways of fixing things and wrong ways of fixing things.

When I replaced that switch, my cruise worked fine. Years later, the cruise started acting up again. I went right to that switch, replaced it, and the cruise was again working fine.

Here is the part I can't remember. I don't remember if the air leak occurred only when I stepped on the brake or not. I think it was when I stepped on the brake pedal.

That's a maybe clue for you. Sorry that it's the best I can do.

stonefly

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JoeZ

Posts: 938
Joined: Dec 2008

Saturday January 09, 2010 06:48

Without actually putting a hands on, I'll try to give you a few tips. I have seen engine brake and cruise switches on the charge valve for the trailer, maxi valve, foot valve, clutch, and a signal from the throttle pedal as well as the dash switch. Without any one switch doing it's job, the system fails. Just jumping the switch doesn't always work......some are open and close switches, those are simple......and some are open grounded and close not grounded and vica versa. A FEW TIMES I have seen the engine brake and cruise both quit at the same time. Sometimes a switch is dual function. (It's that California thing)

The cruise has be activated and to have signal that the brakes are released, clutch is out, truck and trailer brake valves are NOT applied and the vehicle has speed for it to work.

My best guess would be that possibly when the valve was changed, a piece of foreign matter got into the switch or it is disconnected.

We even had a few people that had a valve replaced and they eliminated the switch because the generic replacement valve didn't have a port for a switch.

-------------------------
One of the last 2 Stroke mechanics left.
44 years in the business and worked on everything from 53 series to 149 series. Winding it down now...time to move on.

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stonefly

Posts: 286
Joined: Feb 2008

Saturday January 09, 2010 08:41

One more thing about that cruise. If it's not working, you're not missing much.

As much as I liked my cruise control, I realize it was costing me a lot of hard earned bucks.

My truck was a used fleet truck with only the basic gauges. I didn't install a turbo boost gauge until a couple years ago. When I did, it opened my eyes. The cruise can cause you to use a lot of fuel unnecessarily.

If the cruise is on, and you hit a grade that causes you to lose speed, the cruise will put the pedal to the metal. If you're loaded heavy and pulling a grade, you'll only lose a few mph if you use the lightest foot possible, and then let the down grade get your speed back for you...free. What it costs in time at the end of a long run through hills is only a few minutes. What it saves in fuel dollars, divided by whatever small amount of time you lost, calculates to a dollar per hour figure that is so high you'll want to leave that cruise turned off.

I now use my cruise only on absolutely flat terrain or when I'm so tired I'll sacrifice the money it's costing me to use that cruise.

For years I was getting between 5 1/2 to 6 mpg with my series 60. I was happy because that was about 1 mpg better than I was getting with my old Big Cam 350 and the Road Ranger RT 12609 without an overdrive and 371 rears.

I wised up. I started using ribbed tires for the drives instead of lug, as much as I like deep lug tires. I kept all my tires at maximum inflation. I quit using the cruise. I slowed down a little. I quit idling the truck for long periods. I made all these changes at once.

My fuel use jumped to between 7 and 7 1/2 mpg. That is actual mpg calculated by miles driven divided by fuel pumped into the tanks.

I can't tell you which factors were the most important, but I think the cruise control is a big fuel guzzler, unless you're on perfectly flat Earth.

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stonefly

Posts: 286
Joined: Feb 2008

Saturday January 09, 2010 10:46

I just thought of a little clue that might prove more useful to you.

Which switch might be the first to get pitted and start behaving intermittently, or perhaps quit altogether? Would it be the switch that gets used the most?

Since I only use the clutch when starting or stopping, and since the brake switch is the one that would undergo the most use, my guess would be that the switch which operates when you step on the brake would most likely be the culprit.

That is to say the repairs done at the shop were correct. If somebody goofed up when they worked on your truck, your problem becomes more difficult because then you'd have to find someone else's mistake. In that case, what Gone Fishen and JoeZ said would steer you better. Try and look at the places where the shop guys did something that might have been a goof-up.

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henboy1

Posts: 37
Joined: Jan 2010

Saturday January 09, 2010 14:28

<< I just thought of a little clue that might prove more useful to you.

Which switch might be the first to get pitted and start behaving intermittently, or perhaps quit altogether? Would it be the switch that gets used the most?

Since I only use the clutch when starting or stopping, and since the brake switch is the one that would undergo the most use, my guess would be that the switch which operates when you step on the brake would most likely be the culprit.

That is to say the repairs done at the shop were correct. If somebody goofed up when they worked on your truck, your problem becomes more difficult because then you'd have to find someone else's mistake. In that case, what Gone Fishen and JoeZ said would steer you better. Try and look at the places where the shop guys did something that might have been a goof-up. >>

<< I just thought of a little clue that might prove more useful to you.

Which switch might be the first to get pitted and start behaving intermittently, or perhaps quit altogether? Would it be the switch that gets used the most?

Since I only use the clutch when starting or stopping, and since the brake switch is the one that would undergo the most use, my guess would be that the switch which operates when you step on the brake would most likely be the culprit.

That is to say the repairs done at the shop were correct. If somebody goofed up when they worked on your truck, your problem becomes more difficult because then you'd have to find someone else's mistake. In that case, what Gone Fishen and JoeZ said would steer you better. Try and look at the places where the shop guys did something that might have been a goof-up. >>

I pretty much gave up and put everything back toegther in the dash.My last effort was to look deep inside the dash to find out what the heck they unplugged and the only unplugged connectors do not even go into each other.Those two connectors must have been for test purposes.I put in the switch from freightliner and went for a road test.....but nada.Not even when I reversed the position on the wires going into the switch.I thought about changing out the MV3 to my old one but my mech. didn't think that would fix it.My old MV3 wasn't even bad, and it was just the switch.The TA guy just starts changing stuff.When he puts everything back together and still hears the leak, he advices me that he only had 2 yrs experience and that I should wait till the other guy reliefs him.The other guy comes in and then he realises that the air pressure switch was the problem and not the MV3.Then they start the clock again and change the switch.$550 later and driving down the road I realise my cruise is not working.They adviced that I could go to another TA to find out if it was their mistake or not.The other Ta claimed it wasn't soemthing they did to mees up the cruise because the toggle switch for the cruise and the MV3 is in two totally different locations.$94 later at the second TA, I am driving back on the road with no Cruise.
For $94/hr which TA charges, next time I am going directly to freightliner.I bitched but , I had no choice but to pay.
I just need to dig my foot into the pedal rather than using the cruise.
Thanks guys

-------------------------
Independent trucker
Stockbridge, Georgia

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