1G Cruise control issue

[Freddyk79]

'91 GST. 100% stock

Trying to diagnose my no cruise.

Vacuum line is intact, clutch pedal switch works. Amber light in the knob works, green light in the dash lights up. Won't hold speed. Here r my questions:

Can the black box mounted to the firewall go bad?

Fuses should be ruled out since.the green light comes on correct?

Where is the "brain box"?

Any other tips?

After reading others posts its pretty much the brain or pedal switches most.of the time eh?

 

[BlueArcher]

Brain box is above the fuse box under the dash, should be gold in color with a label for part # MB649317

Image: http://i.imgur.com/pIPbVs2.jpg

 

[BlueArcher]

Might have spoken too soon, it seems after closer inspection that part # is for non-turbo cars... I will see if I can confirm this.

Either way, the location should be the same.

 

[BlueArcher]

Okay, there is some ambiguity on exactly which part is in your car, but I am now leaning towards MB686860 and it is a gray box

http://i.imgur.com/bvjJhOj.jpg

 

[PlanZero]

OP, why don't you just delete the Cruise control? I never realized how sluggish my throttle response was until I got rid of it. Best $18 I spent, and got rid of all that clutter.
If your set on keeping it I'm sure you can find someone just giving it away.

 

[Freddyk79]

Found it! Pain in the nutsack getting it out tho. Thanks for the replies!

Dead set on keeping it. 90% of my driveing is freeway.

 

[Freddyk79]

Are the fwd and awd cruise control brains interchangeable?