Hold On

Well after logging lots of miles to OCIC and home, I`m really hoping to get cruise working again.

I have done all the vacuum cks and everything is tight and system holds 20psi indefinitely.
I have done the mechanical/tempostat tests and all is good.(kinda fun revving the engine with a handheld remote starter button connected to the harness plug. lol )
I have done the electrical tests on the harness plug and all have checked out per the manual.
I have done a visual inspection of the box and resoldered any suspect looking joints
I have substituted another box with no change.
Unit was working recently on a "when I friggen feel like it " basis but now nothing!!

I have a couple questions. Is there some sort of switch at the brake pedal that causes system to disingage when breaking? and how exactly does the speed sensor at rear wheel setup work? Or am I totally off on both of these??

Any other suggestions are greatly appreciated. Thanks, Kevin Flynn

Alan

Its connected to the main (lights) switch on the brake = cancel (and for MT cars there is a seperate switch on the clutch too = suspend).

Speed signal comes from the digi-dash on later models or the pulse sender on the earlier cars.

Alan

Hold On

Mine is a 1983 S. Automatic.

So if the brake light circuit operates correctly, we can eliminate that.

Is this pulse sender or speed sensor a stand alone part somewhere in car, or is it integrated into trans or dash. I see it indicated in wiring diagram but no location given.

Lizard928

This is a timely thread!

I just went through this on my 87 5 speed (same system as your 83).

Everything checks out. 3 brains tried. Resoldered one first.

All pinouts check out perfectly, including testing for the speed pickup.

To check the speed pickup though simply put an ohm meter between pin 11 and 12 of the plug and roll the car forward or backward slowly. The ohm meter will switch between 0 and inf resistance.

However after all the tests (and vacuum system repairs), everything checks out perfectly. The system still will not hold, but if I push the stalk forward it will actuate and begin to accelerate. If I release it will not hold though.

I will be doing more searching of old threads as I know this was gone over years ago.

SeanR

Are the connetions on the stalk good? Have you tested the continuity on all three settings from the plug? Not done this myself, but in my mind it sounds ok.

depami

One little issue with your test: PSI is pressure and the cruise works on vacuum!

If you actually checked PSI, then that may not mean anything! You need to check vacuum! Which is measured in inHG (inches of mercury).

You could use a Mity-Vac? Or a refrigeration pump with a vacuum gauge. A shut off valve would be good to isolate the device under test (DUT) from the source (refrigeration pump).

I use one from an old freezer and it works quite well..

WICruiser

I have a similar problem except I have not gone beyond checking the pin to circuit continuity in the brain box. In my case there is no engagement - no indication that the system actually turns on (when driving - volta meter checks are all correct at the plug and the actuator pulls the cable provided the right vacuum level and electrical jumper.

My speedometer is not consistant so I will need to confirm the pulse signal but otherwise I am stumped.

Lizard928

After searching and seeing the other thread it was obvious it was the brain. I took the one I had rerun most of them on and just redid them all.
Took it out, put it in the car took it out, and IT WORKS!!

At slower speeds I had a 4-6kmph variance. At highway speeds I had a 2-3kmph variance. All in all I am happy and can live with that.

Hold On

My typing error Yes I checked vacuum using my Mity-Vac