98 - 02 Cruise control woes

[MadMaximus]

I have run out of ideas. Since I am not familiar with the servo valve setup, does the servo valve include the vacuum actuator that pulls on the throttle, or is the vacuum actuator separate?

- John

Its all one unit[/QUOTE]

 

[MadMaximus]

You have changed everything but the cheap switches in your steering wheel.

You cant buy the switches anymore, so I got some used ones, tried those not change, but my originals back after cleaning them (I found they are serviceable despite what a dealer would tell you), still not change.

 

[MadMaximus]

I am going to go through everything one last time tonight. I may pull back some wire loop and look for frayed wires or something.

If I still cant figure it out... I will probably break down and put in an aftermarket unit.

 

[MadMaximus]

2001 Dodge Ram Cruise control FIXED.

I FIXED IT!!!!!

I decided to retest everything from the procedure I found at mopar1973man.com , and this time follow the directions more closely. The link to that procedure is here: https://mopar1973man.com/cummins/ar...4/p1595-speed-control-solenoid-circuits-r128/ .

The issue ended up being the wires from the main harness to the speed control servo, had internal damage you cannot see. I made a video on how I fixed it. I have posted it here for your viewing pleasure:

Basically I was able to disassemble the connector, remove the wires, crimp and solder new ones, reconnect to harness and put it all back together and bam! it worked!

Here is a photo of the repaired connector:

 

[petersonj]

Excellent. Really glad that you kept pursuing the matter. You never would have been happy with an after-market cruise control.

So, the wiggle test was the key.

The best part of your diagnosis was that you didn't throw parts at it and still got it resolved.

Excellent video, by the way.

- John

 

[Ozymandias]

Good point, I'm going to check mine to at that location as I have an intermittent fault where the cruise just drops out sometimes immediately sometimes after hours of driving.

 

[MadMaximus]

Good point, I'm going to check mine to at that location as I have an intermittent fault where the cruise just drops out sometimes immediately sometimes after hours of driving.

Also check the harness where it plugs into the PCM on firewall, connectors C1, C2 and C3. I have heard some folks had problems over there too.

 

[LorenStrodtman]

I tested the resistances of the switches and they seem consistent but the manual does not say what the resistance really is, so I cannot say if these are good, or not.

For future readers, this afternoon I tested my original switch that I had replaced with no improvement, so currently assume the switch is good.
ACCEL: 15k Ohms
CANCEL: 1k Ohms
COAST: 3k Ohms

Switch number 56021332AB

 

[MadMaximus]

For future readers, this afternoon I tested my original switch that I had replaced with no improvement, so currently assume the switch is good.
ACCEL: 15k Ohms
CANCEL: 1k Ohms
COAST: 3k Ohms

Switch number 56021332AB

Are you getting a trouble code along with your malfunctioning cruise control?
I did find you can take the switches apart and clean them. They are pretty simple and because they are low voltage they should not really wear out unless they have gotten some corrosion on them.

I was going to do a video on cleaning them, but decided not to, since that was the culprit in my case.

 

[Ozymandias]

I replaced the (faulty) Range Sensor on my transmission last week, I also replaced the pressure transducer at the same time that sent my Trans randomly into limp mode.
....no more drop outs of the Cruise Control since.

Leaves a lot of question marks....

 

[MadMaximus]

I replaced the (faulty) Range Sensor on my transmission last week, I also replaced the pressure transducer at the same time that sent my Trans randomly into limp mode.
....no more drop outs of the Cruise Control since.

Leaves a lot of question marks....

Really? I have not heard of either of those, but I am insanely curious. Can you tell me what those are exactly and where I have them? Is this for an automatic trans?

 

[Ozymandias]

Yes this a 47/48RE thing.

The range sensor is sometimes called a park/neutral switch which it isn't anymore as it provides the information to the dash (and ECM) what gear you are in. The one that I have was introduced to the line with MY '00. It is fixed to the outside left side of the transmission.
It is hard toget a quality part as Dodge canceled it from the parts they sell and all aftermarket stuff is just cheap.

The pressure transducer that we use is inside the pan, passenger side.
It measures the Governor pressure and tells the ECM to either lower or increase through the Governor solenoid. This pressure is important for the shift points and the overall performance of the trans.
It is a fairly cheap part which tends to fail, there are improved versions available, you want the one from ROSTRA with the white back plate. This version transducer came with MY '98.

 

[MadMaximus]

Yes this a 47/48RE thing.

The range sensor is sometimes called a park/neutral switch which it isn't anymore as it provides the information to the dash (and ECM) what gear you are in. The one that I have was introduced to the line with MY '00. It is fixed to the outside left side of the transmission.
It is hard toget a quality part as Dodge canceled it from the parts they sell and all aftermarket stuff is just cheap.

The pressure transducer that we use is inside the pan, passenger side.
It measures the Governor pressure and tells the ECM to either lower or increase through the Governor solenoid. This pressure is important for the shift points and the overall performance of the trans.
It is a fairly cheap part which tends to fail, there are improved versions available, you want the one from ROSTRA with the white back plate. This version transducer came with MY '98.

I am not sure about the pressure transducer, but i could defiantly see how the range sensor could affect the cruise control, if the PCM thinks the truck is neutral or park, that will disconnect the cruise, so that makes sense that could have caused it in your case. Where were you able to find a new range sensor?

 

[Ozymandias]

I got a decent one from DNJ
https://www.dnjcomponents.com/products/12410c

Not only Park/Neutral but as well when the sensor does not report D, then there is no OD shift commanded.

In your transmission it is basically a switch and the Range is read in the dash itself if I remember correctly.

 

[LorenStrodtman]

Are you getting a trouble code along with your malfunctioning cruise control?

No. My guess is that it's a busted wire but have not taken apart anything to check voltage/continuity/resistance. I just dug out the switch I had in a box and tested resistance on it.

 

[MadMaximus]

So, my cruise control is still working... sort of. Keeps cutting out and throwing the speed control solenoid circuit code again. I decided to try replacing the neutral saftey switch and when I went to that, I discovered that the three wires next to the connector that plugs into that have no insulation! (see photo) Do you think this is causing my cut out issue?

 

[petersonj]

Since you are still getting the same 1595 code, I think the fault has to be in the same circuit that you did your previous repair (circuit highlighted in your wiring diagram). The bare wires in your photo obviously need attention, but if they were causing problems, I think you would get a different code or no code at all.

- John

 

[MadMaximus]

Since you are still getting the same 1595 code, I think the fault has to be in the same circuit that you did your previous repair (circuit highlighted in your wiring diagram). The bare wires in your photo obviously need attention, but if they were causing problems, I think you would get a different code or no code at all.

- John

Yeah... I was afraid of that. I think I may just start running new wires between point A and point B following the diagram. Its' got to be one of those.

 

[Ozymandias]

Mine gave no codes with the broken range sensor but the cruise failed through it, so fix these cables.
You can buy a pigtail connector with 4" of cable for a proper repair.

 

[petersonj]

I think I may just start running new wires between point A and point B following the diagram.

Or, just do some more wiggle tests...

- John