I have a 1997 Dodge RAM 1500 Laramie SLT (V-8, 5.2L). My cruise control has always worked, until last week when it suddenly stopped working. The lights come on in the steering wheel module when I turn it on, but hitting the set switch does nothing.

At the same time I've also had the check engine light come up a few times and I had it diagnosed as a vacuum issue (code 411, I believe). My ABS light is always on too, but that's been like that since I bought the truck. Occasionally the ABS light will go off for a while, then come back on.

I did some research on this forum and the Web and discovered that with the cruise control often its a vacuum line, so I checked under the battery at the servo and found one small line that was just hanging there. I went to the auto parts store and got a replacement line and stuck that in there, but the cruise still doesn't work and the check engine light is still on.

I've seen enough diagrams and possible solutions to make me dizzy and I don't want to pay a garage to wrangle this out for me, so I thought I'd ask here about this and see what you Dodge RAM guys have to say. If you need any more info or anything just let me know.

Thanks.

 

When you replaced the line did you check the module for any other signs of battery acid damage? When I bought my truck the module had a hole burned right through one of the small vacuum ports within the module itself. If that checks out follow the lines to / from the module and assure that there are no other breaks / cracks

 

I got under there and looked around, but I don't see any holes or damage. I was trying to get the battery shelf off, but I have one stubborn bolt that won't budge. From what I can see there doesn't appear to be any damage from any acid or anything else.

What's next?

 

If I remember correctly your cruise will not work if you have an abs issue.

Often times it's the sensor on the rear of the axle (I think 97s had those)

If that's not it it gets much more interesting to diagnose

 

Is that the speed sensor on top of the rear differential?

 

That would be the one. However, on your truck, it shouldn't matter. Truck gets its speed sensor signal from the trans/t-case sensor. (depending on 2 or 4 wheel drive.)

If the lite comes on, that implies that the PCM is getting the hint that you want cruise. Next, I think I would test the switch. Wiring diagrams are in the factory service manual, that you can download from the service manual thread in the FAQ section here. (get the 96 version, closest to your year truck.) All the switches do is modify a voltage signal to the PCM, make sure those work first.

 

Where's the switch and how do I test it?

 

The switch is on your steering wheel, and you test it by using a meter, and seeing what voltages you see on the correct pins at the PCM. (or, in the column, if you can't draft another warm body, careful there though, airbags can kill.....)

Where in michigan?

 

I saw a PCM in the manual, but it's located in the engine compartment. I didn't see a switch anywhere. I have no idea how to test this and if it involves messing around with the steering column or getting creamed by the airbag then I'd just as soon leave it alone. The truck runs fine, even with the lights on and the cruise not working.

I live in Spring Lake, MI.

 

Other side of the state. Bit of a cruise.... (pardon the pun.)

Your cruise switches are on your steering wheel. Those are the switches you want to test.

PCM feeds power to the switches. Depending on which switch you press, it applies resistance to the circuit. Different switches have different resistance, so, you see different voltages on the return circuit at the PCM.

You are interested in the yellow wire, with red trace, in the gray connector at the PCM. (think its the middle one.) The feed wire is also in that connector, so, you can either scrape a bare spot on the wire, and test voltage that way, or, unplug the connector, and check resistance across pins 11, and 32(red with light green trace). (if you look really close, they are numbered on the PCM side of the connector.)

Got a multimeter?