1979-1993 & 94 Conv [Subscribe to Daily Digest] |
 | [Main C900 Bulletin Board | BBFAQ |
Prev by Date | Next by Date | Post Followup ]
Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Cruise control: gee whiz, if I only had a brain? Posted by Saana88 [Email]  (#207)  [Profile/Gallery]
(more from Saana88) on Mon, 19 Feb 2007 18:00:39
Members do not see ads below this line. - Help Keep This Site Online - Signup
|
I just finished troubleshooting Sadie's (defunct) cruise control. (1992 convertible, 126k) As doubtful as it sounded to me at first, she's got a bad cruise module (a. k. a. silver deathpod).
Symptoms: When I got the car, the cruise would work around a third of the time, and cut out from time to time. Sometimes it would set for ten seconds, other times it would last indefinitely, other times it would stick for around five minutes.
Two pedal switches later (the brake pedal switch was slowly leaking vacuum), the cruise would work around half of the time. Another couple of weeks and it would work a third of the time. When it got nice and warm out it would work around ten percent of the time.
I changed the inductive pickup sensor on the back of the speedometer. No change. At least three separate times in this span I put a vacuum pump on the main line and drew all the air out of the line. The accelerator pedal dropped and stayed all the way down for at least five minutes each time.
I changed the stalk switch because it was about to fall apart and didn't latch on for left turns, big surprise.
(prepare to) Fast forward a year and a half to now, Sadie's sleeping the winter off in the garage, and with no seats and not carpet in there I figured I'd tool around with my voltmeter. Here is a brief exerpt:
First step: pull out the vacuum pump and hook it up to a power source. It sucked, so the pump is good. Reconnect.
Next, check that the stalk switch is going what it's supposed to (electrically). It was.
Next, check for power and ground at the control module harness connector. Got power, got ground, so that's okay.
Next, check for power and ground and signal generation at the (new) sensor on the back of the speedometer. Got power, got ground, and it generates some sort of varying pulse when I manually spin the wheels (front of the car in the air). That works, even though I am incapable of spinning the wheels by hand at a fast and steady enough rate to see if the signal is fine, but the faster I spun them, the greater the signal, so I'm happy.
Next, I went into the wiring diagram and checked that every input (eleven of them) at the harness connector was doing what it was supposed to. It was.
Still no cruise. Bad module?
Now I wonder what "Nicht werfen" (written on the outside of the module) means. Probably "Do Not Open" which I'll oblige since I have to send the old one back as a core.
I'm guessing that the slow collapse is similar to what would happen if something in the module was dying (open caps or solder joints breaking down with heat or dying transistors). Am I right or did I miss something? I'm kind of new to the whole cruise thing, my other 900s didn't have it. I take that back, the '90 base car had it added aftermarket by some idiots who didn't put in a clutch switch, so the first time you don't cut it out you are in for a big surprise! (and the second and the third on and on ad nauseum until I just quit using it...)
Thanks for the input.
, Mon, 19 Feb 2007 18:00:39 <-- Viewing This Message
, Tue, 20 Feb 2007 20:45:48
, Wed, 21 Feb 2007 05:16:18
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
