Cabriolet Warning Light Troubleshooting

[Montanaro]

I have an 88 911 Cabriolet that I have owned for several years. Every summer when I take it out I try to figure out what is wrong with the top warning light. So far to no avail.

Here is the situation- the cabriolets (with an electric top) have a red warning light located on the top of the dash just left of the speedo. This light comes on if the top is not latched in either the full open or full closed position. Under normal operation, when you start the car the warning light will come on and then goes off after a few seconds (very similar to the brake system warning light).

This is what happens.

When I open or close the roof, the light goes on during the transition then goes off when in the final position. If I start the car it goes through the normal test process then goes out. It may do this during another few cycles but eventually it will stay on.

If the engine has started and the light is out it has never come on as long as the engine is running. It is always after the engine has been off, started and then it stays on after the initial check system functions.

I have checked all the limit switches and they are fine. I have checked them to make sure they are reading correctly even though the light is lit. I have opened the roof control box and there are several relays in there. The contacts all look find and there is no visible sign of burning, cracking etc.

I realize this is more of an annoyance than anyting else but I just can't get myself to pull out the bulb. I would appreciate it if anyone has any ideas, suggestions or has experienced this themselves and resolved it?

Regards,
David

[kkkarpuk]

My '87 does the same thing. When I bought the car the PO had taken the bulb out. I put a new one in when I replaced the guage bulbs and acts exactly as you describe. At times the light will stay on after starting but never comes on after it has gone out until I restart the car. I subscribed to this thread as I would like a solution to this as well.
Ken

[turn6]

My '86 does something similar..I just turn off the motor at my earliest convenience and momentarily cycle the top the reverse of its present status. I just attribute this to a quirk. After 16yrs of ownership if it ain't broke...

[kkkarpuk]

I have been doing the same, turn the car off, touch the rocker to lift the top slightly then lower the top fully. This has usually worked to turn the light off. I was hoping to find a solution to this rather than spend time chasing a fix. I would rather spend the time driving....

[Montanaro]

Spring and convertable time is here again and I am bumping this message to see if anyone has ever figtured out this issue with the 911 cabriolet electric top warning lights.

[geoz]

nope, mine is fine ... just to confirm there are cars out there that work as designed

[Montanaro]

Bump - convertible season starting - wonder if anyone has figured this out....

[fasterlaster]

What a strange thing. I don't have a cab, but do happen to have the Bentley schematics. There isn't much complexity in the light itself. Appears to be fed via a red/black to the speedometer, then red/yellow to the lamp and on to the switch. The other end of the light is a brown/red wire that goes to the control unit. It certainly seems it is something internal to the control unit based on how simple it's designed outside of the box. Hopefully this is helpful in some way.

[Cenzzo]

As far as that pesky light, I actually found a fix that works every time. I have a battery cut out switch on my battery, and one day, while cutting the power for something completely unrelated, I got back in the car and fired it up and the light was out! So, the next time I put the top down, and the light stayed on, I tried the cutout switch again, light went out. Seems like it just likes a reboot? Whatever works.