Door opening issues

[Kitchski]

Hi all,

Unlike a garage to ask for assistance on a forum, we don't see too many Cerberas at our gaff. We've got one in at the moment with a few issues which are areas we've not really played with before. It's a 4.2, I believe around a '99 vintage.
Basically, there is an issue with the door opening, where neither door will open, nor will the window drop.
It's the same on both sides, though when the car arrived it was tempremental as opposed to inop. On a number of occasions, pushing the driver's door switch opened the passenger's door!

Having gone into the boot and pulled the control box out, there is a clicking present (presumably from the relays on the bottom C/B) when operating the switches from both sides, yet no movement from window or door. Oddly, there is still clicking even if the car is "locked."

We're still hunting around and researching on this as in fairness we tend to stick to the mechanical and chassis side of the TVR world, and more often than not it's the older models we specialise in. However, I want to try and help the customer has he's had a bit of a nightmare with it so far and I thought who better to ask than the people who run and repair them at home!

Any help appreciated, but to summarise:

• Doors won't open from inside or out from switches
• Windows don't drop when attempting to open doors
• Little black locking switch on centre console either flashes green or stays green statically and doesn't respond to input
• Clicking present at control unit in boot. No water ingress present.
• We have both immobiliser fobs and both appear to work fine
• Car will start and run no problem

Any advice on where to start looking would be very much appreciated.

Thanks

Rich

[pmessling]

Centre console button is to turn off the outside buttons to stop people opening either door.

I guess that should be green when pressed thus the outside buttons not working.

[Cerbieherts]

Do the windows work with the window switches?
Have a look again at the control unit in the boot. Hold it so that the plug with only two wires in it (one red, one black) is to the left. There is a long plug to the right of it, and this contains the wiring for the locks/buttons and window control. Pin B3, which should be red, should have 12v from the alarm unit when it's disabled..

[spitfire4v8]

A door button should never open the door on the other side. There's 4 return circuits one per release button but they're separate right back to the control box. The whole host of issues suggests a control box failure rather than lots of individual issues. Can you try the box on another cerbera.?

[Kitchski]

pmessling said:

Centre console button is to turn off the outside buttons to stop people opening either door.

I guess that should be green when pressed thus the outside buttons not working.

Same as with the Chimaeras then. Sometimes it's on static, sometimes it flickers, sometimes it's off. Makes no difference what happens if you press it.

Thanks

[Kitchski]

Cerbieherts said:

Do the windows work with the window switches?
Have a look again at the control unit in the boot. Hold it so that the plug with only two wires in it (one red, one black) is to the left. There is a long plug to the right of it, and this contains the wiring for the locks/buttons and window control. Pin B3, which should be red, should have 12v from the alarm unit when it's disabled..

The windows work with the switches, yes. We've now managed to operate the windows from the boot, so the wiring is ok on that side of things. B3 appears to be pink on this loom though!

Thanks

[Kitchski]

spitfire4v8 said:

A door button should never open the door on the other side. There's 4 return circuits one per release button but they're separate right back to the control box. The whole host of issues suggests a control box failure rather than lots of individual issues. Can you try the box on another cerbera.?

I can beat that now too....driver's door button just popped the boot open!

It also looks like both the door solenoids are fried. We've only just replaced a failed one on the nearside, and it's killed that already.

Does anyone know where the driver's door pin switch is? There's one present on the circuit diagram, but we can't find anything other than a little black bung in the sill which an M6 stud presses against (or in this case, misses and punts a chip into the bodywork!)

[Jhonno]

The stud is the reed switch, and the black disc the magnet, which tells the ecu if the door is open/closed..

[Tanguero]

There is a magnetic reed switch in the bottom edge of the door and a corresponding magnet in the sill on the body. Replacement part details in the alternative parts sticky at the top of the forum.

A quick way to tell if it is working is that the interior lights will only go off automaticaly when the door control box thinks both doors are closed. This can be overridden by the light switches but on the auto setting on the switch you can tell if the reed is working.

A truism is that around 98% of door problems on Cerberas are cured by cleaning or replacing every corroded multi-way connector inside the doors.

Edited by Tanguero on Wednesday 4th September 16:45

[Cerbieherts]

There is also a Door switch is in the latch on later cars. Are the plugs the right way around in the control unit? They should look like this:


It does sound like the control unit has died. If the interior lights stay on but the magnet/switch is working it also points to this...

[Byker28i]

how does pressing a door button open the boot. I thought that was directly wired?

You need the wiring diagrams to help

http://www.thetvrsite.com/cerbera/wiring-diagrams

[Steve_D]

Byker28i said:

how does pressing a door button open the boot. I thought that was directly wired?

You need the wiring diagrams to help

http://www.thetvrsite.com/cerbera/wiring-diagrams

Each door button is wired separately back to the control box.
The boot will open randomly from either an inside or outside door button which is why we have come down to the conclusion that it has to be the control box.

If we press a door button we sometimes get 12v at the door motor. Sometimes that 12v does not release which will be why the lock motors have burnt out...and why the battery keeps going flat.

Testing the wires (Controller unplugged) I can test each button, door pin switches, window motors, lock motor wires (Although both lock motors are now burnt out).

We don't have a spare controller to finally prove the point so the ideal solution would be to find a company that can test then repair this one. If it comes back 'no fault found' then we have more wiring issues to resolve.

Anybody know a 'controller repair man'?

Steve
Southways

[Tanguero]

Never used them myself but I have heard good things about them. http://pselectronicsolutions.co.uk/repairs.html

[Steve_D]

Tanguero said:

Never used them myself but I have heard good things about them. http://pselectronicsolutions.co.uk/repairs.html

Edited by Tanguero on Thursday 5th September 08:44

Thanks
Yes found that site from elsewhere but the contact phone is switched off and the mail bounces back.

Steve

[Englishman]

Paul was about to go on holiday when he fixed a board for me so expect he is still away. Recommended though!

[WhyTwo]

I sent my control box off to Paul in July after my passenger door and boot stopped working (drivers door works fine). I suspected perhaps some dry joints on the pcb. He tested it and it came back with a clean bill of health. I now suspect it could be a dodgy earth so I'm going to clean them up when I get the chance and see if that helps. As I say the drivers door works so In this weather I tend to prefer driving it than trying to fix the issue so it's had to wait.

Apparently there are 4 earthing points, anyone know which would be the right one(s) for passenger door and boot control?

[Tanguero]

WhyTwo said:

Apparently there are 4 earthing points, anyone know which would be the right one(s) for passenger door and boot control?

The control box earths to the point in the boot above the fuel tank.

[Steve_D]

WhyTwo said:

.......my passenger door and boot stopped working........... I now suspect it could be a dodgy earth so I'm going to clean them up when I get the chance and see if that helps........

I would start by pulling the trim behind the B post and finding the wires to the door lock motor. Unplug and apply 12v to the motor. I'm betting you will find the motor burnt out. They are not the most robust of mechanisms. Do the same for the boot motor.

Steve

[WhyTwo]

Cheers Steve and Tanguero. I'll take a look over the w/e

[Kitchski]

Thanks for all the advice guys. As Steve's found out, looks like the control unit itself is up the spout. It's now on it's way to Paul Smith.

Cheers