Howdy all,
I have the classic non functioning cruise control issue, and heater probs. So the only leak I found was the hose broke going in to the servo under the battery. fixed that, but many posts show that the diaphram in the sensor/servo is most likely shot as well.
Does anyone have a source for the unit, other than my friendly dodge dealer?
Thanks a bunch, just trying to get my ducks in a row before summer season hits.

 

If you still have issues with the heater control, then you likely still have a leak.

Is yours 4X4, and have you checked the lines underneath?

I could see if only the Cruise didn't work, or only the heater didn't work, but both not working indicates leak.

For grins, do you have a MityVac to try on the heater control?

 

4x4 is working, checked all the lines under the dash too. some say the diaphram in the servo is a common culprit. tough to hear a leak over the mighty 5.9.

 

Since you fixed the hose is the cruise the only thing not working?

I bought a servo from the dealer for $32 a couple years ago but someone said they are now on backorder for a long time.

 

Still no luck wwith the vents. I have floor board only. Plugging up the outlets gave me enough to keep the windshield clear this winter, So i'll check for mechanical problems (somthing jammed in there?) when I tear out the dash for some noise control work.

 

Yep, when you don't have vacuum, it defaults to Defroster. You likely have issues with either the actuator or the control. Cruise servo is probably out as well then.

Just saw some on Fleabay, not sure what year you are working on, but they had a new 97-99 on there for 70 bucks.....

 

So I dug in to the dash today, and found that the lever came off of the heater control arm for the floor heat. Now that works... Still tracking the cruise issue.

 

I saw that add, but no picture. I didn't ask a question, but I suppose I won't get an answer with doing so...

 

Back when I used to work on these trucks all the time, I saw the occasional servo failure, but the #1 failure for cruise was vacuum leaks in the area of the driver side battery. Another occasional problem was column stuff, like broken wires to the clockspring connector, failed clockspring, failed switches, etc. I think the number one electrical failure was bad brake light switches. They have 3 sets of contacts, so just besause your brake lights work ok doesn't eliminate it as a cause. It just seems to need a bit of resistance in the contacts that input to the PCM to cause trouble with the cruise. For the low cost of the switch, it might be worth throwing a new one at it to see if it fixes it.

Does the green light come on, on the switch when you turn it on?

 

I checked lines for leaks and found one there the frist go around. No one will say it.s easy to hear a leak when the engine is running. But when i get out immediatly after shutting it down, I can hear the hiss right where the servo is. And yes I've rechecked the line since. Even tried a 95 servo, but the cable was shot and the wiring a bit different.
No to the green light in the dash or on the steering wheel. it's a 97slt if that makes a difference

 

If the light on the switch doesn't come on, it sure sounds electrical. There is a yellow/red wire that brings the power up to the switch through the clockspring, that circuit may be broken, either within the clockspring, or the wires that go up the column to the clockspring. It could be other things too, but I'd pull the covers off the column and have a peek there. They like to break just before the clockspring connector from the movement of the tilt steering.

 

The brake light sw has 2 contacts for the brake lights and I believe the rest are for the cruise. As these sw are very unreliable could that be the problem.

 

I'll be ripping into the column then...

 

I would check the brake light sw first, if I remember right with the pedal not pressed one set should be closed allowing power through for the cruise. The other 2 sets should be open. One set is for the brake lights the other set is for the PCM. When the pedal is pressed the PCM contacts supply a ground signal for the PCM.

 

I went down the brake light road...didn't change anything.