Cruise Control Light

[trailhead]

My cruise control light was always staying on, but the fly-by-wire cruise didn't work.  After much problem solving, I finally took the 2001.5 Ram 2500 6 speed diesel to the dealer.  Trust me, it wasn't my first choice.  Anyway, they told me that the PCM didn't know that I ever had a cruise control equipped truck.  The tech claimed that part of the PCM hard drive was dead.  

The dealership ordered a PCM, but somewhere along the line there was a mistake and they received a PCM for an automatic transmission. They didn't install it.  Instead, I ordered a PCM from NAPA for about $450.   The PCM came in and the dealership agreed to install it, labor free, since they'd screwed up so many times previously.   So, they installed it.   Then I got a call saying they still couldn't get the cruise to respond and had determined it was the instrument cluster.  Cha-ching!  The dealership tells me they can get a new cluster for $790 plus core deposit.   I decided I'd buy from O'Reilly who wanted $330 plus core deposit.  Well, it was supposed to take a month to get the part from O'Reilly.  Nope.  A month later they can't get the part, and they tell me that they might be able to get it if I wait another 4 months.   So, I gave up and told the dealership to order their $790 dollar part.   Three days later (yesterday) they get the part and try to install it.  Tech calls me up, "The part that came in is Canadian, and I can't install a Canadian cluster into your Dodge."   I assume it was due to KMH instead of MPH.   Anyway, I've had it at this point, so I told the guy I just wanted my truck back, and that I will never be back.  Guy ordered (or coincidentally received) the wrong PCM AND the wrong cluster.   He seems entirely incompetent.  After 3 months and almost $1000 nothing has changed on my truck, the cruise light is still on (always) and doesn't work!  In case you're wondering, the cluster does not throw any codes when tested.  

 

I wish I wasn't so dense in this area.  Can the cluster really be the issue?  Can I get one from a junkyard?  Should I keep trying to find a new one somewhere, or can someone just fix the one that I have?     Should I put pressure on the dealership to get back some of the money I squandered with them?    Thanks for all of the advice!

 

 

[Mopar1973Man]

Posts like this, make me lose faith in ASE certified mechanics.

As for getting any money back I doubt it.

As for diagnosing this... There is a few different thing involved here. You have the ABS computer bringing the speed signal. The central timer under the dash receiving the input from the steering wheel. PCM that has the cruise control software. Then feed throttle information to the ECM by wire.

So as for the cruise light being on I would start at the steering wheel control and central timer.

Edited December 19, 2015 by Mopar1973Man

[IBMobile]

2 hours ago, Mopar1973Man said:

Posts like this, make me lose faith in ASE certified mechanics.

 

Where in the above post does TRAILHEAD mention that the tech who worked on the truck was ASE certified.   I've worked for dealers who would hire a 'tech' with no experience, no qualifications, only a tool box and let him wrench on customer's cars until his comeback rate was more than the profit.  As for getting money back: i'd be talking to the general manager or owner of the dealership to get back any money paid to them for diagnostics or what ever.  They know they messed up by installing the PCM no charge.

 

Edited December 20, 2015 by IBMobile

[Buzzinhalfdozen]

Some of the best techs I know are  certified/uncertified. I've also seen some real hacks that are certified/uncertified. When I was wrenching my employer would give me a small bonus for every certification I got so it was worth it. 

[dripley]

When I went thru my debacle with a rebuilt ECM, I kept the second one even though the cruise light was constantly illuminated and the cruise did not work. When that one died a year later the light was still illuminated. I had the ECM replaced with a Cummins one. The light went out and it and the truck ran fine afterwards. I cant say that is definitely the OP's solution, but it did solve my issue.

As far as mechanics, certified or not, they are like superintendents, some are better than others.

[Mopar1973Man]

Sorry, for stirring the ASE pot. Up here most all the dealers pride themselves on their big shoulder rocker with the ASE on their shirts. That why I made the comment.

As for the cruise light issue, you could systematically disconnect each module one at a time and test and see what triggers a change or the light to go out. So if you disconnect the ECM and the light goes out then you would know the ECM plays a role. Make sure when disconnecting you have the key off and do one module at a time.

[RdH81]

I'm having major issues with my 01' as well. The cruise light stays on and has no function.  So far the dealerships (yes more than one) has successfully succeeded in spending my money on new vp, new ecm, new steering wheel controls, new speed sensors in rear axle and both front hubs, new front hubs, new clock spring and countless hours of diagnostic fees.  

Please help I'm at my wits end and the wallet has suffered enough from incompetent so called "mechanics" at dealerships.  I just picked the truck up today from the 4th dealership and their response was we replaced your hubs but have no clue why the cruise will not work. Here's the bill.  

[dripley]

6 hours ago, RdH81 said:

I'm having major issues with my 01' as well. The cruise light stays on and has no function.  So far the dealerships (yes more than one) has successfully succeeded in spending my money on new vp, new ecm, new steering wheel controls, new speed sensors in rear axle and both front hubs, new front hubs, new clock spring and countless hours of diagnostic fees.  

Please help I'm at my wits end and the wallet has suffered enough from incompetent so called "mechanics" at dealerships.  I just picked the truck up today from the 4th dealership and their response was we replaced your hubs but have no clue why the cruise will not work. Here's the bill.  

is yours and auto or a manual? Is the light on all the time?

Edited February 4, 2016 by dripley

[JAG1]

I would try to get most all the money back. Go thru the better business bureau if you have to. They will resolve issues like this. Don't forget to read the fine print on the back of the service contract...... I don't think it says they have the right to try out different parts..... they are supposed to do a complete diagnostics.

[trailhead]

I'm the OP from way back in 2015.    

 

2001.5 24 valve 6 speed manual transmission  Cruise Control is fly by wire.  There is no servo and no vacuum involved in the cruise control.  

 

My problem is that the cruise indicator light below the odometer on the instrument cluster is always illuminated.  From the second the key is turned to the “on” position the cruise indicator light is on and cannot be turned off.  The cruise does not work at all.  

 

Part 1

On the brake switch there are six wires.  

 

1 (Wt/Pk - Brake Switch Sensor PCM) Shows no voltage with brake off (plunger depressed). This makes sense because the PCM doesn’t want to know unless the brake is applied, at which point this pin shows nearly 12 volts.  

 

2 is the ground.  

 

3 (YL/LR - Speed Control Supply) Never showed voltage (brake on/off, key on/off).  

 

4 (dark blue/red) Also never showed any voltage.  

 

5 (white/tan - trailer brake) showed 12 volts only when brake was applied, otherwise nothing (makes sense).  

 

6 (pk/Dark Blue) showed 12 volts at all times.  

 

I’m replacing the brake switch regardless, but if there are any red flags here, please let me know.  

 

Part 2

Under the dash on the giant connector (C130 I think), I found a red/light green wire that I believe is the “Speed Control switch Signal” wire.  

 

Key off, no voltage.  

Key on 4.5 volts brake engaged and disengaged.  

 

I was using the “Signal Ground” to test the voltage.  This is a black and light blue wire also going through the connector (C130).  

 

While testing the voltage on this circuit, I pressed the cruise switches to test their resistance.  

 

ON/OFF Cruise switch - voltage reduced to less than .7 volt.  

 

“Set” button.   Voltage reduced to 3.3 volts.  

 

“Accel/Resume” switch - 4 volts.

 

“Cancel” button - 1.7 volts.

 

“Coast” button - 2.7 volts.   

 

My understanding of the Speed Control is that when certain conditions are met, Pressing the speed control switches (resistors) sends a specific voltage to the PCM and ECM.  The computers recognize specific voltages and digitally send outputs to various components required to control the speed.   

 

The “On/Off” button sends a voltage to the PCM.  The PCM recognizes the voltage and sends a digital message through the BUS to the Cluster indicating that the cruise indicator should illuminate.  At the same time, the PCM sends a signal to the ECM, preparing the ECM to store a speed.  

 

When the “Set” button is pressed the PCM receives a specific voltage and translates that digitally to, the ECM, which stores a speed and uses various inputs (vehicle speed etc) to control the APPS, injectors, and VP44 to maintain the speed.  

 

The “Coast,” Cancel,” and Resume/Accel” buttons all send specific voltages which the computers analyze accordingly.  

 

My best guess up to this point is that the PCM is recieving a very low voltage, approximately 1 volt.  This is interpreted as someone pushing the ON/Off button, and not releasing it.  Therefore, the PCM always instructs the cluster to illuminate the “Cruise” light under the odometer, and it can never record a speed or perform any of the other cruise functions because it is receiving one constant, and very low voltage.  I have no idea.  

 

Any corrections to my understanding and/or any suggestions would be mighty helpful.  I’m just about to throw in the towel.  Also, if you read this far, you're a saint.  Thank you!

 

Also, the PCM has been replaced.  The dealership installed one I purchased.  Nothing changed.  I’ve never used a Scantool, is it possible that the cruise voltages have to be programmed in?  Or that the PCM wasn’t set up correctly?  

 

[dripley]

I had the same issue with a rebuilt ECM back in 09. The first one was bad but the second one worked, all but the cruise. The light was illuminated constant but ctuise did not work. The problem did not exist until I installed that ECM. I did not investigate the issue as you have nor would I begin to know how. That ECM only lasted about 13 months and I had it replaced with one from Cummins. Cruise worked fine after that and to this day. 

 I am not saying your ECM is bad, apparently you know much more about it than I. Just giving you my experience with a very similar issue. I never did find out what caused the problem.

[Sycostang67]

The funny thing about ECM's, when someone orders one through our store, at least in the commercial department.  The commercial managers have learned to order 2-3 at a time because the 1st one rarely works. 

[trailhead]

Thanks guys.  I called a place near Denver about a genuine Cummins ECM - $2600.   I also contacted the dealership, haven't heard back about a price yet.   NAPA rebuilt - $375.   

 

Also, the new brake switch didn't change anything. 

[dripley]

The Napa rebuilt is most likely a PCM and not an ECM. A lot of places do this.

53 minutes ago, trailhead said:

Thanks guys.  I called a place near Denver about a genuine Cummins ECM - $2600.   I also contacted the dealership, haven't heard back about a price yet.   NAPA rebuilt - $375.   

 

Also, the new brake switch didn't change anything. 

 

[carl]

Trailhead i'm very interested in the solution to you'r cruz prob, it sounds very similar to mine except the FBW part. please keep me posted with your progress and results and i will try to do the same . FYI i've been researching this prob for a while now and BRAVO also thx.

 

 

[trailhead]

Back again.  This time, I think I've found a shop that has some problem solving abilities although I don't have cruise...yet.  So they replaced the clutch position safety switch, and they replaced the clock spring.  Turns out there was a problem in there after all.  They have continuity to where they need it, but when they hook up the scanners, they still can't find where the vehicle is equipped with cruise control.  Long story short, they now say the ECM (on the driver's side of the block) is for an automatic transmission.  They want to replace it.  They say it is not the stock ECM.  They say the ECM has been discontinued, can't get it from Napa, Dodge, etc, but they can get it off the internet from somewhere in New York.  They want $1500.  I'm leaning toward buying it, and if this works, well dripley was right all along.  I'll let you know.  It's been a long process.  My only question is, any suggestions on where to get an ECM that isn't 1500?  Or, if I am going to spend that kind of money, should I call up Cummins and see if they have one?  Thanks for any help you can give me.  

[dripley]

I think finding a new will be difficult and  very expensive. I would want to know more about their 1500 dollar one before purchasing. It may be possible to reprogram the ECM you have but I dont know that. ACS is a vendor here who could answer that question. They are in the vendors forum with contact info. Be worth a phone call. Their ECM repair is cheaper than 1500 bucks.

 The more I have thought about the one I had it seems it was for an auto and not a manual tranny.

[Dieselfuture]

I would definitely call ACS and see what they say and if they can help, they had ecms for sale out right for 600/700 bucks programed to your truck with latest software. 

[Evan]

Moparman.

 

The auto ranch in mtn home has some of the worst mechanics in the country.

 

ASE Certified means nothing. 

There are a few good mechanics in mtn home and they certinaly do not work at the dodge dealer. 20 years ago tod McCurry ran a good business but that's no longer the case.

[Mopar1973Man]

On 5/9/2019 at 7:50 PM, Dieselfuture said:

I would definitely call ACS and see what they say and if they can help, they had ecms for sale out right for 600/700 bucks programed to your truck with latest software. 

 

That is my first choice. ACS is a good company that will handle the job properly and most likely for less money.