Ive been working through my non operable rear quarter windows and conv top. Without much success. To date i ve cleaned and tested all console switches and they work, checked all relays to be working, grounded handbrake to remove it from operation. Checked fluid in pump. What would i look into next? Thermal breakers? Trans rotary switch? Ive been putting the top down manually but it be nice to get the rear quarters working . Thanks for any advice on how to proceed

 

The following will help:
- model and year of car.
- what exactly happens when you press the lower switch? First thing should be the quarter windows lower. Do they do that? Do you hear any noises at all?

 

1995 2+2 nothing happens . No noise no window movement. Thanks

 

As you know, there are 3 key conditions:

- Power On
- Handbrake on
-Transmission in Park or Neutral

Set / check all 3 conditions, but ensure you do it at the ecu, as previously mentioned, eg don't ground out the handbrake at the handbrake switch, do it at the ecu.

With all the conditions verified AT the ecu, operate the switch and check that input is going to the ecu. Then check what is happening at the ecu outputs to the relays.

Good luck

Paul

 

My hand brake is grounded at the ecu in the trunk. How do,i check imput?

 

I did a bit of digging on the internet.

What I believe I found..is this:
- the ECU is not Involved in the convertible top operation…per attachment of ECU. This makes sense as in that timeframe the ECU only controlled the engine functions.
- There is a convertible top control module…per attached pictures, including showing the location. Check the fuse, and check all the relays.
- Attached is schematic of 1995 Convertible top control,schematic. If you want tips on where to start after checking the fuse & relays..ask.
- Alos make sure when you actuate the hand break, the light comes on in the desolate. This confirms the switch works.

 

The above schematic is hard to read. Here’s the entire electrical manual, where you’ll find it at figure 28.

https://search.app/UjkEM9pzVu1Qsfxv8

 

XKDreams,

When we say "ECU", we're referring to the "Convertible control module" not the Engine ECU.

Paul

 

I have check all six relays in the trunk for continuity and operation by supplying 12 volts to each. I have replaced the 30 amp fuse back there with a new one. I grounded the handbrake at the roof control module located by the trunk relays. Prior to doing that the brake light would illuminate when i engaged the handbrake but since grounded i dont know if it still does. My question is how do i check that theres a signal getting to that control module in the trunk when i press the center switch on the console ?

 

Also , might be unrelated but the little red light below the cigarette lighter has only illuminated once . Could there be something about my security system thats preventing the roof and rear quarter windows from operating?

 

Here’s what I suggest as next steps. . Hopefully you have access to a digital multimeter, and you’ll likely need an assistant unless you have very long arms.

• 1) With the ignition on. Put the positive lead of the dmm into the convertible top connector pin #7, top down, and the negative lead to ground. With the dmm on DCV, measure the voltage….you should read a strong positive voltage. Then press the top down button, and the voltage should go to “0” volts. If it doesn’t go to “0”,then either the switch is bad, it the wiring from the switch to the controller is bad.
• 2) Repeat the above, except probe pin #6, top up…again, you should get a strong positive voltage, then press the top up switch and the voltage should go to “0”. If it doesn’t go to “0”, then either the switch is bad, it the wiring from the switch to the controller is bad.
• 3) Measure voltage at pin 8, it should be 12 VDC. If it’s not 12 vdc, disconnect the connector and measure the voltage at the pin. If it is now 12 vdc, the controller is shorted, if it’s not 12 vdc, you have a wiring issue.
• 4) Repeat preceding either pin 8.
• 5) Assuming the above test of pin 8 & 12 are good measure voltage between pin 8 & pin 1, it should be 12 volts, that will test the ground.
• 6) Repeat step #1. Except probe voltage aat pin # 10, parking break switch, then activate parking break and go”then activate parking break and voltage should go to zero.
• 7) probe voltage at pin #9, park & security inhibit. With transmission in P & N, and security disarmed, voltage should be “0”.
• 8) Test voltage at both sides of the thermal breakers, to ground…should be 12 vdc
• 9) Test voltage at both sides of the thermal breakers, to ground…should be 12 vdc

Ok, that’s a good start. Let me know the results of the above, and then, I’ll get back to you with the next steps.

 

wardhill68,

I'd test in the logical order of:

1. Power & Earth to the Hood ECU
2. Manually set the Restrictor conditions (Handbrake & Transmission Selector)
3. Check Hood Switch operation
4. Check output voltage to Hood Up / Down relays

So:

- With ignition in Pos 2, Check voltage on Pins 8 & 12 (White & White / Pink wires)
- Check Hood ECU Earth integrity - Pin 1 (Black Wire)
- Manually Earth Handbrake & Transmission Selector inputs - Pins 9 & 10
- Earth the Hood Down Switch input - Pin 7 (I think it's a 5v, not a 12v signal when open)
- Assuming all above ok, press Hood Down switch (or Earth Pin 7 at Hood ECU), and simultaneously check for voltage output to Hood Down relay - PIn 3 (Blue / Orange Wire)

The thermal breakers are only for the rear windows, they don't affect the Hood UP / Down operation

Good luck

Paul

 

When you say “pin” do you mean the pins in the wiring connector by the top module in the trunk? If i pull that apart i can access the pins in the harness side of the module, correct?

 

You just want to backprobe the relevant pins on wiring connector whilst it is still connected to the Hood ECU.#

Paul

 

Thank you for the replies. I have a good point now on how to proceed. I truely appreciate it and will update soon . Regards,Jeff