Cruise Control Diagnosis

[Poor-sche Lover]

Hi,

I'm trying to figure out why my cruise control doesn't work. Just so we're clear, I understand "real" Porsche owners don't need cruise control. Personally though, I'd like to have as many of my car's features actually operate as I can.

Anyway, the cruise does not work at all. It will not even set. So, I got out the Bentley and went to work. Unfortunately, I didn't get past Test 1 in the troubleshooting guide. It says that I should have an infinite reading between terminal 3 and ground. I get a reading of something like 92,000 ohms. The guide doesn't give a reason for why this would be. Any ideas?

I also checked several other tests, and it failed nearly every one of them. I assume I have multiple system failures, but I'm trying to figure out what direction to go before I start buying parts. If you can lead me in the right direction, I'd appreciate it.

Thanks.

[janz]

When I was having trouble with mine not working I got all kinds of crazy readings doing the tests described in Bentleys and from the posts here. I bought a used one and it started working once I plugged the vacuum line back in but stil wasn't right, surging and stuff like that. Sent out my origonal to Beckmans for a rebuild and now it works pretty darn good. I'm with you on getting everything the car came with working again like it should.

[kodioneill]

Understanding the VDO Cruise Control Amp

looks like a bad servo if you confirm i have one for $40.00

[Poor-sche Lover]

Wow! That link was WAY above my simple head. I don't know if it's the brain yet, as it gets disconnected as part of the troubleshooting guide. As for the servo, again, the guide indicated that the servo WAS bad, but it also indicated the clutch switch was bad, the column switch was bad, . . . . . . I think it must be something deeper than EVERY part of the system is broken. That just doesn't seem right.

By the way, my car is an '88, so I don't have the vacuum servo.

Anything else I can try?