My 1994 convertible top isn’t working. It isn’t the parking brake - I had that bypassed, so it isn’t necessary to apply the brake to lower the top. I checked the fuses in the passenger side and in the boot. They seem fine. When I press the top button, there is no whirring sound from the motor and the back windows don’t go down.

Can anyone suggest what could be wrong? I’m guessing the top switch in the center console has gone bad.

Thank you

 

Switch would be easy to check, just bypass the wires.

How about the relays? Those are where the pump is.

And I'm assuming the pump isn't set to manual.

Other than fuses, the car needs to know that the car is in Park, and not in any gear, including neutral.

 

Thank you for your help!

I’ll bypass the wires on the switch and check it. I’ve been wanting a new switch anyway because it’s faded.

The top hasn’t been bypassed.

How would I know which relay could be bad? There are several. I don’t even know how to test that a relay is good or bad.

 

I have had similar problems and it always came down to the switch. For whatever reason, the contacts seem to get funky. They can be taken apart and cleaned. Also the blade connectors seem to lose connectivity and need cleaning.

The top relays are the 2 in the middle of the relay pack by the pump, one for up and one for down. The other 4 are similar for the quarter windows. Relays don't fail very often. Checking them for function is pretty easy. I believe that those are 4-post relays but the technique is the same for a 5 post. A relay provides a control signal to tell a power connection to connect. Usually 30 has continuous power and the other side is 15 (which is the connection to the thing being powered). The control signal is 85-86 or 87. With a 12 volt source connected to the control side (positive and ground), you should see connectivity on a volt meter between 30 and 15 and likely hear a click.

 

Thank you for this great information! I really appreciate it. I ordered a new switch. The old one was showing wear and the window switches had been replaced and look new, so the faded switch for the top didn’t match the window switches. Once I put the switch in, I’ll update this post and let future readers know if the new switch solves the issue. And thank you for letting me know about the relays!

 

Danny,

If you consider the problem logically, you can avoid replacing parts unnecessarily. The wiring diagram is very clear and is your prime info source here.

As the hood doesn't lower OR the windows go down, it is just possible, but very unlikely, that it's the relays as that would mean that at least 3 relays have simultaneously failed - very unlikely.

It also can't be the hood being in Manual mode, as the windows would still go down.

You've bypassed the handbrake, so it's not that. It could be the autobox selector switch signal, and it would be easy to verify and bypass that at the hood ecu, to eliminate that.

So, you could easily check all the input and output circuits by back-probing the pins on the hood ecu and probably work out the problem there.

As you're replacing the hood switch anyway, it's possible that's the problem, and replacing it will eliminate that. But again, check the signal at the hood ecu.

Also, I'd strongly suggest that you lift the skislope to access the switch. It's really easy to break the plastic tangs on the switch surround or the switches themselves when trying to remove and replace them. It's much safer to lift the skislope and access them from below.

Good luck

Paul

 

Paul,

Thank you for taking the time to analyze this. It is very helpful and I appreciate it very much.

My new switch isn’t due to arrive until next week. Once I install it, I will post an update.

Danny