funxman

Well I got my car back on the road again, so back to where I left off before mm and TB work.

I have went through the steps for diagnosing the cruise control up to the last step of checking the speed sensor. I've jacked up one rear wheel (left side) and done the ohm test spinning the tire but the meter is picking up nothing at all. The speedometer works fine.

Is this the same sensor as the speedo?
Does this test appy to 5-speeds as well?
And where is the sensor located? Any suggestions.

Thanks

SharkSkin

Try jacking up the other wheel... IIRC it's on the right side. You are looking for the exact same pulse that the speedo uses.

joejoe

Is the brain o.k.? Tried sending you a p.m. but must not have gotten it I guess. As we are in the same town might be kinda neat to get together and swap stories.

SharkSkin

I'm a couple hundred miles NorthWest of you... just North of San Jose. No, I didn't get the PM... I haven't met a 928 owner yet that didn't like to swap stories, but Porterville is a bit of a hike.

joejoe

That is a bit away Shark. The PM was sent to funxman who is in the same town (actually I live in the country) Although if you're ever down this way..... Did you make sharktoberfest? It was a blast again with lots of people, cars, and stories.

SharkSkin

DOH! Sorry, you guys with no avatars all look alike. Yeah, it's a ways. I went to SF '04 & '05, missed all of the big 928 events this year since I moved. You guys are all outta luck, I'll be back in '07.

funxman

I am not sure why, but I got busy at work, and when I had time to get back out, I did get the signal from spinning the tire. Maybe my wire apparatus to the gage had a bad connection.

Well apparantly it is the control unit "brain" cuz everything in the WSM checked out. I took it out and didn't see any bad solders, but touched some of them anyways.

I read in a post somewhere that some electrics are interconnected. One problem I have is the brake light warning comes on "!" every time I start the car. When I tap the brake pedal the dash light goes out, no more warning "!" until the next time I start the car. I can hear the relay when I turn on the cruise and turn it off. I am wondering if A-the brain is simply no good, or B-the brake light issue could be killing it.

RngTrtl

I have the same brake light warning until I touch the brake after I start the car...Is this not normal?

SharkSkin

Brake warning is normal. It's to verify that your brake lights are functional. If it does NOT go out first time you hit the brakes, you have a problem.

Clean off the varnish from the backside of the board and resolder all of the joints. Having narrowed the problem to this box, you have nothing to lose(unless you're really bad at soldering). More info here.

funxman

Finally SUCCESS!!!. After about a week of parts all over the passenger floorboard and six times of sitting down at the table with spotlight, magnifying glass and solder gun, I apparently hit the bad solder joint/joints. I was about to give up hope. But this morning I plugged it in and zoom!

I have never seen a cruise control system that allows you to shift a 5-speed without turning the system off-it just takes a little break while you do the clutch work.. AWESOME!

Thanks Dave and rennlist friends for information and another step in the right direction.

SharkSkin

Cool! One more project you can chalk up as a success!

Lqqrraw

Since we're on the subject may I ask another cruise question? I tried using my cruise the other day and noticed it wouldn't stay engaged at the needed speed. If I hold the activation lever to the "SET" position the engine accelerates, speed increases and the pedal goes down but when the lever is released nothing! Any ideas? I'm almost caught up fixing stuff and what do ya know...one more thing pops up, I LOVE MY 928...really!

Thanks from a new member...
Brian
'84 928S
Blue/Camel (Beige/Tan...whatever)

funxman

I'm pretty new to these cars as well, but most problems are pretty predictable and repairable . If you have a workshop manual, it does a pretty good job of narrowing down the fault. From outside, you need to check for vacuum leaks, inside the car you will do some electrical diagnostics that will check everything else but the brain. If everything checks out, then break out the solder gun.

Do a little searching if you do not have the WSM, the procedures have been posted here and there.