Cruise Servo Bench Test?

[LorenS]

I have removed my cruise servo and before I throw $100 at a new one, I want to make sure this one is actually bad.

 

Ohm meter reads 4.5 between ground pin and one of the others, 8.5 ohms to the other two.

 

I can apply vacuum and apply power to check solenoid operation if needed, does anyone know if it takes a 5 volt signal, or does PCM send 12 volts?

 

The idea of hooking volt meter leads to the truck-side plug and driving over 30 MPH to see if the PCM sends a signal just seems like a last resort.

 

EDITS: I can confirm it takes more than 5V to operate the solenoids. Also, I believe mine is bad because when I applied vacuum and energized either coil, it behaved the same as when the "vent" solenoid was energized.

 

I'll buy a new one and report back.

Edited December 9, 2018 by LorenS
Add updated information.

[LorenS]

Installed MOPAR cruise control actuator part number 1673355, and for the first time ever, my cruise (kind of) works!

Of note:

1. This part number rotates the unit about 90 degrees due to the stud locations.  It was still very easy to install, but I don't know if it will affect the solenoid operation (and may be why my cruise still doesn't act 100% correct).

2.  My old unit was stuck in the closed position.  No matter where I applied my 12V power, it never released vacuum.  The little foam filter was crumbly, so perhaps this stuck position was due to it eating part of the foam.

3.  Just the opposite, this new unit wouldn't hold a vacuum no matter where I applied 12V, though I heard the solenoids clicking. FSM page 8W-33-2 shows that pin number 4 is the ground wire (black).  However, I was the vacuum pump, connected via a piece of tubing - perhaps I just don't have what it takes to be a working girl, if you will.

4.  While I installing this new unit, I noticed my ground wire to the G100 connection is in very poor condition.  The insulation on the wire is missing for about 3"!  Alas, the sun was setting Sunday evening so it all went back together.  Will address that problem next weekend at the latest (I hope).  Factory service manual page 8W-90-20 shows where this ground connection is located, basically behind the windshield washer fluid.

5. Yes, the wiring is the same as a 2005, per 2005 FSM page 8W-33-4 (gas only - all diesels this model year use the ECM for speed control, like the manual transmission versions of 2nd Gen trucks).

6. I think my ACCEL/COAST/CANCEL button is bad, but have no idea how to test it.  A trip to the junk yard this past weekend yielded zero trucks with my style of buttons to try out or compare electrical resistance.

 

I hope this helps anyone in the future, even if it is rather incomplete.