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Chrysler Repair/Cruise control failure


QUESTION: Hi Roland,
I just lost my cruise control. I luckily cleared codes last night by disconnecting the battery. Today I got "Code 34 - Open or shortened condition detected in the speed control vacuum or vent solenoid circuits."
By sheer luck, as I was cleaning the inside of the engine bay, I also had my ignition fully on,(but car not started and the cruise control was turned on), I happen to move a large wrap of wires that were bent to an almost 90deg angle by the drivers side shock tower and had four wires leading to a connection on the speed control unit (I think its vacumn assist?).ANYWAY, as I pushed into this wrap of wires I could hear what sounded like a relay clicking in the speed control unit. Does this likely mean I have a break in the wires somewhere in that large wrap of wires??!! As I said, I could move the wrap of wires slightly by the bend in it and hear a relay clicking on and off. I tried to position the wires using a rag into differnt positions to see if that might be the problem, and then ran the car and tried the cruise with no luck. Given the current fault code 34, am I looking at tearing into that wrap of wires, or do you have any other thoughts. I did check the fuse for the speed control with a meter: it checked good.
Thanks again,
PS I'm waiting for the wiring diagrams you sent me to continue trouble shooting my hi-beam switch problem, and confirm it is the switch. I do believe you are 100% right: I think it'll be the switch.

ANSWER: I suspect there is either a cracked wire or a cracked insulation around one or more of the wires. It would be good to know the wire colors involved in the relay which I can get for you and share that information tomorrow.

---------- FOLLOW-UP ----------

Mass of wires expsosed after opening wrap
Mass of wires expsosed  

plug wires going into the speed control
plug wires going into  
QUESTION: Hi Roland,
Further to your helping me with the speed control problem on my 92 LeBaron 3.0 convertable 4spd.
I've enclosed two pics: one of the mass of wires and one of the wires and colours going into the plug that goes into the speed control.
In case they don't show well, they are: Orange/red stripe, Green/red stripe, Blue/red strip, Black,
With the Black and Blue/red stripe I get 12v intermittantly as I gently move the wires.
Upon opening the wire wrap I can see there has been previous repairs, as there is shrink wrap around the black wire before it splits off to the speed control and I think the brake level sensor. Regardless, I tried wriggling the black wire with no change regarding power to cruise control plug.
Two thoughts: Now that I've opened the wire wrap and loosened the wires it's almost impossible to get the shorted wire to engage hot again.\
I tried wriggling/tugging gently on each wire and watching the meter for 12v hot with no luck. I'm thinking of just cutting out and replacing the "fix" on the black wire as that's the only place I can guess the fault is.
Also, any suggestions how to work around how tight it is in there?? Most of the wires take off through the firewall on drivers side: I'm guessing the relays and fuse box.
On the passenger side, the wrap goes throught the firewall right in the far corner: I'm guessing it goes to the computer.

PS I notice I don't get a chance to rate you when I ask for a follow-up question. This seems unfair as you are in a competition and the follow-up questions can be long and complex. Perhaps you can't answer this but I'm wondering if it would be better if sent each question to my previous question as a NEW question. ?
Thanks Roland,

Hi Rick,
The four wires to the speed control are shown in the '92 wiring diagrams to be:
black: ground to left side fender shield behind battery
dark blue/red: goes to a 6-pin plug at the stop lamp switch under the dash mounted on the steering column support and which is operated by the brake pedal (this tells the servo that you stepped on the brake and thus cancels the speed control function).
light green/red: goes to pin 53 at the powertrain control module and is called the 'vent'
tan/red: goes to pin 33 of the powertrain control module and is called "cont"
The speed control system is vacuum powered so that is why there is the vent wire.
I would suggest that you check for continuity of each of those wires as described and replace/repair any that are flaky. It is not clear to me which if any of those wires carry 12v but none seem to be directly connected to a fuse.
I don't know why there was no opportunity to rate a should be there.
Thanks for doing the rating and nomination, and don't go to the trouble of initiating new questions which would have the undesirable side effect of loosing the continuity of the discussion.

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Roland Finston


Free fast answer to your repair question about a Chrysler/Dodge/Plymouth car, minivan, SUV, or truck. Problems with electronically controlled engines and transmissions as well as body wiring problems are my specialty. This free troubleshoot advice forum helps you diagnose faults, minimize repair costs or do-it-yourself.

I answer questions seven days a week and respond to you in about 30 minutes. "Maxed Out" means I am answering another question, briefly unavailable, or asleep overnight, so try again later.

I have do-it-yourself experience (50+ years) and a library of 100 1982-2011 Chrysler factory shop manuals and 20 multi-manual Chrysler Corp. CD's.

I was voted "Top Expert" 2010-2015, here at AllExperts, and have answered 20,000+ questions.


Five decades as a 'do-it-yourselfer' on domestic and imported cars.

Yahoo Autos Group called The Chrysler Lebaron Club (co-moderator)

Advanced degrees in Physics/bruised knuckles

Awards and Honors
"Top expert" of 2010, 2011, 2012, 2013, 2014 and 2015 here at Allexperts. Quickest "average response time" at Allexperts (currently no. 1).

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