Fred's 964

The top on my '92 Cab intermittently fails to operate when trying to put it up. It always goes down OK. It goes up smoothly and evenly when it works. Once or twice, I started and stopped the engine a few times and it worked. I found a crack in the plastic on one of the limit switches (on the right side) so I replaced them. It seemed OK for the next few times, but is doing it again. The top completes its cycle perfectly including the latches when it works. When it doesn't work, it acts like it isn't getting power (the lights don't dim, no power draw). There have been times where I'll come back later and it works, but I usually close it manually, latch it, unlatch it and reopen it manually, then reattach to the gearboxes.
Has anyone experienced this? I may replace the up/down switch, but don't want to begin chasing parts if I can avoid it. Has anyone had to replace the switch?

jimq

I know I have read on here somewhere maybe the 993 board about bad solder joints in the controler box under the dash.

chancecasey

Sorry, no ideas but I'm interested in what the fix turns out to be - I have the opposite problem - once in a while, randomly, when putting the top DOWN, it will stop going back after about 1 second. I just push the switch the other way to fasten/close it, then try again and it always goes down.

A guy I know had the little brass gears in the latches completely strip out on his.

Would some lubrication somewhere be good for cab tops? (no jokes, please )

Fred's 964

Thanks, jimq, I located the link in the 993 board. I'll hunt for the controller tomorrow.

Fred's 964

Jimq, here's the link. (I don't know if I attached the link correctly) If not, search the 993 board. It was submitted by swmic and is called convertible top problem solved. Thanks Jim.

Wachuko

Fred, while you are at it... remember to check from time to time the bolts that hold the top's transmission in place. When those come loose... well... you do not want those bolts to be loose. Broken frames and all that bad stuff...

jimq

Jaime I took a quick look back there and dont see how to take the side covers off. What is the trick in doing that. I need to check mine also to make sure they are tight.

Wachuko

Very easy... there is a plastic black cover that has a slot in the middle (looks like a big plastic bolt head) on the side cover (one on each side). Unscrew that and you should be able to take the side cover off (back first and front slides out). That is all there is to it... That will give you access to the top's transmission.

A few photos of what you will find in there are in this thread: Cabrio Top Problems

Fred's 964

I went to the 993 thread jimq told me about. (thanks Jim) I saw a familiar pattern with some other cars and it made sense. I located the Cab top controller, (it's right behind the dash near the headlight switch behind a silver controller with a VDO label on it ) and removed it. (I wished I was half the height that I am, tight space) I removed the controller covers and looked at the solder connections and found several cold solder joints. I resoldered the suspect connections, reassembled it and it works perfectly. I took pictures if anyone is going to do the same repair. The bad joints were at the pins that go into the wiring harness connectors. I'll work the roof several times this week as the weather is going to be great for a convertible. I'll follow up when I'm sure it is fixed.
jimq, I'll come over if you want to check your top transmission bolts. My side covers have that black plastic cover Wachuko told you about, but also has a screw just below the speaker. It should pull a bit toward the rear to release it.

Fred's 964

Thanks for the reminder, Wachuko, I've had the side panels off several tomes, but was focussing on electrical issue and forgot to check them. The top was replaced about a year ago, so I hope they tightened them then. I'll check this week.

jimq

I am going to be around the house friday afternoon after 1 if you are off. We can put yours on the lift if you want to check anything out and run the scantool again to see if those codes on the CCU came back up. Give me a call if you want to get together.
PS Thanks Jaime I will look tomorrow.

Fred's 964

I removed the top controller a couple of weeks ago and resoldered any suspect solder joints. JimQ and I both checked all our cab gearbox bolts and they were all tight. (unrelated, but we have been wanting to check them) I thought the problem with the top was fixed by resoldering, but today I tried to put up the top and nothing.... It is doing exactly what it did before the controller resolder attempt. I'll check the current at the switch and motors to try to find the problem. The switch is $70 so I don't want to change it unless I determine it is bad. Ironically, I hope it stops working long enough to troubleshoot it. I love a challenge, but intermittent problems can be a bear to find.
Does anyone know where I can find a schematic of the cab wiring? I know where the components are, but knowing what is in the circuit may help me figure it out. Any suggestions from someone who has had similar problems would be welcomed. I'll check the harness and controller connections again when I check the switch. Being 6' 2" tall doesn't help when under the dash...

jimq

The good thing is Fred its going to be in the mid to high 80's thru the weekend. Top down weather
Sorry the fix didnt work.