Tvr Cerbera 1994

[Marty19671]

Hi

I am fitting a new alarm on this vehcle, meta system previously removed , can anyone help with central locking wiring colours to control cdl and location for this. I am assuming you are just controlling the door motors so wired for universal motor driven.

Also there is a problem, that the garage thougt was with old alarm where the windows dont always go down and up on opening and closing, is it likely to be the magnetic contact switches, can you explain how the windows part works when opening and closing the doors. is there a way to test things at cdl/window module.?

Many thanks in advance
Martin

[Juddder]

Marty19671 said:

Hi

I am fitting a new alarm on this vehcle, meta system previously removed , can anyone help with central locking wiring colours to control cdl and location for this. I am assuming you are just controlling the door motors so wired for universal motor driven.

Hi!

For the wiring colours I would go through the wiring diagrams at

https://tvr-cerbera.co.uk/wiringdiagrams.html

I think this would be the one to study first

https://tvr-cerbera.co.uk/WorkshopWiringDiagrams/D...

Marty19671 said:

Also there is a problem, that the garage thought was with old alarm where the windows don't always go down and up on opening and closing, is it likely to be the magnetic contact switches, can you explain how the windows part works when opening and closing the doors. is there a way to test things at cdl/window module.?

Many thanks in advance
Martin

From my experience with my car and the control boxes this is how I believe it works

The button on the bottom of the wing mirror triggers the Door Control Box to drop the window slightly and then trigger the actuator that is connected to the mechanical mechanism on the door

When you shut the door the magnetic sensor in the bottom of the door triggers against the magnet in the sill of the body, and this triggers the Door Control Box to raise the window at that point

If you get really stuck The Abacus Car Alarms team specialise in TVR and similar alarms so will probably very kindly help out - you can find them at [e-mail] and http://www.abacuscaralarms.co.uk/

HTH! Alex

Edited by Juddder on Tuesday 14th February 12:38

[Juddder]

BTW Just in case you didn't know the Door Control Box is in the boot of the car, behind a carpet cover on top of the fuel tank

Here's the pinouts and wire colours complete with pictures from recently fixing mine

https://www.pistonheads.com/gassing/topic.asp?h=0&...

[Marty19671]

Hi, both of you many thanks for your help so far.

The original Meta alarm has been removed, and an older Clifford Concept 650 alarm has been fit, with I believe also has a wireless fuel guard, which is another issue as I think this is active and the vehicle has lost power to the fuel pump, but I have no idea where this is located or looks like, and also the issue with the windows not opening and closing properly, but first I want to try and understand how to operate central locking with a new alarm.

I had already found the Door lock control unit, but I couldn't see any connections coming from the existing alarm to this unit except one wire, which appeared to be coming from the old Clifford alarm via a relay going to Connector 1 (J45) 17-way housing - black/red wire at this unit, which I have now identified as being A8 boot release switch wire. I think this receives a negative from the alarm when a button is pressed on the alarm's remote control to open the boot.

With respect to the alarm controlling the central locking (locking and unlocking the vehicle), the only wire I think from an alarm that may appear to be controlling the locking/unlocking is a pink wire found on (J36) 1 x 12-way AMP Mate NLok pin 5 pink wire, alarm active which goes to splice joint 3 and also looks like (J37) (Alarm accessory socket) 1 x 6-way snap connector PIN 4 alarm active pink wire also goes to splice joint 3 which then goes B3 Pink alarm active at door lock control unit connector 1 (J45 17 way housing)

So my question is does this pink wire coming from the alarm control the central locking lock and unlock, or what is it? and would the alarm be giving out a negative or positive at this wire, otherwise what are the wires to control this or would it be wired to B1 blue/orange and B2 blue/green drivers lock motor at the door lock control unit?

Thanks

[Juddder]

Marty19671 said:

Hi, both of you many thanks for your help so far.

No problems

Marty19671 said:

The original Meta alarm has been removed, and an older Clifford Concept 650 alarm has been fit, with I believe also has a wireless fuel guard, which is another issue as I think this is active and the vehicle has lost power to the fuel pump, but I have no idea where this is located or looks like

The fuel pump is in the passenger rear wheel arch (external) so hopefully you will be able to trace the power from there - there are two cylindrical units there connected in series together - one is the fuel filter and the other is the fuel pump

I'll have a read of the rest of your questions and see if I can answer more later

[Imran999]

Marty19671 said:

Hi, both of you many thanks for your help so far.

The original Meta alarm has been removed, and an older Clifford Concept 650 alarm has been fit, with I believe also has a wireless fuel guard, which is another issue as I think this is active and the vehicle has lost power to the fuel pump, but I have no idea where this is located or looks like, and also the issue with the windows not opening and closing properly, but first I want to try and understand how to operate central locking with a new alarm.

I had already found the Door lock control unit, but I couldn't see any connections coming from the existing alarm to this unit except one wire, which appeared to be coming from the old Clifford alarm via a relay going to Connector 1 (J45) 17-way housing - black/red wire at this unit, which I have now identified as being A8 boot release switch wire. I think this receives a negative from the alarm when a button is pressed on the alarm's remote control to open the boot.

With respect to the alarm controlling the central locking (locking and unlocking the vehicle), the only wire I think from an alarm that may appear to be controlling the locking/unlocking is a pink wire found on (J36) 1 x 12-way AMP Mate NLok pin 5 pink wire, alarm active which goes to splice joint 3 and also looks like (J37) (Alarm accessory socket) 1 x 6-way snap connector PIN 4 alarm active pink wire also goes to splice joint 3 which then goes B3 Pink alarm active at door lock control unit connector 1 (J45 17 way housing)

So my question is does this pink wire coming from the alarm control the central locking lock and unlock, or what is it? and would the alarm be giving out a negative or positive at this wire, otherwise what are the wires to control this or would it be wired to B1 blue/orange and B2 blue/green drivers lock motor at the door lock control unit?

Thanks

The door ECU locks and unlocks the car by watching for a signal from the alarm. When armed, this input (J45 B3) goes high (12V) and the ECU responds by first closing windows and then providing a flashing signal to the green LED on the interior lock button (in front of shifter), of course it also ignores any door/boot opening switches for the duration of the time the alarm is armed.

[Imran999]

For more info about the Door ECU and for a diagnostic flow (at the end of the write-up), see here:
https://www.pistonheads.com/gassing/topic.asp?h=0&...

[Byker28i]

I suppose the other question is - is it really a 1994 Cerbera? I thought the first were 1996?

[Marty19671]

Alex many thanks and Imram thanks for the information on the pink wire and link for full explanation

Edited by Marty19671 on Thursday 16th February 20:45

Edited by Marty19671 on Friday 17th February 12:12

[Marty19671]

Byker yes you are right. sorry the cerebra is a 1996 not 1994 as i said

[Byker28i]

Marty19671 said:

Byker yes you are right. sorry the cerebra is a 1996 not 1994 as i said

Good stuff, I've an early 1997, so if you need to do any comparisons they should be the same.

[Marty19671]

Hi

The alarm I will be fitting is a sigma, it does not give +12 volts when armed which I understand is required at the pink wire at the door lock control unit J45 conn1 B3 for the vehicle to close the windows and lock the vehicle? or is it just disabling the release buttons, and I assume when the 12v is removed the vehicle unlocks? the outer release buttons operate as normal. Obviously, I can just use a relay to covert it but worried about the current draw with a relay always on when the alarm is active, or I could you a 4001 Not gate IC possibly?

So I am wondering are there any other ways to get this alarm to do the locking, any thoughts?

Edited by Marty19671 on Wednesday 22 February 18:01

[Imran999]

The Door ECU “locks” the car by ignoring any signals from the release buttons (all 5 of them) when a 12V signal is applied to the B3 pin on J45. Removing the 12V signal allows the doors to open again.
If the logic on your Sigma alarm is the other way around (provides a 12V signal when disarmed), then you can use a normally closed (NC) relay. You can wire it to supply a constant 12V signal to the Door ECU and then switch the relay with the alarm signal when disarmed, which will remove the 12V input and allow the doors to open.

How that helps (and works).

[Marty19671]

Many thanks for your excellent work, I found one of the problems yesterday with the passenger door pin switch wire at the plug corroded and broken away, causing the problems with the passenger window. This vehicle used pin switches rather than magnetic contact switches.

The other issue was with the CDL with that pink wire B3 J45. I was expecting this wire to not have any voltage on it when the alarm was not active but noticed instead, there were about 10 volts, and to make sure nothing was feeding into this wire at the control unit I cut this wire and the voltage remained high. The doors also hadn't been operating properly, to begin with leading the garage to think it was the alarm.

Now with the old Clifford alarm, I had noticed an external relay that had been connected to the pink wire behind the seats , and on further investigation, I found for normal operation of the doors opening and closing and windows lowering and rasing via the release buttons, this pink wire which goes to the cdl control box had to be grounded at all times, otherwise if left open circuit the door release buttons stop working.

So the door ECU effectively “locks” the car by ignoring any signals from the release buttons (all 5 of them) as you say, when the pink wire going to pin B3 on J45 goes open circuit and it automatically raises to +12volts on its own at the control unit, which in turn locks out all the release buttons, I found with the Clifford alarm via a relay, the pink wire was grounded for normal use, and the relay energized to open circuit the wire removing the ground to stop the release buttons from working. There is no need to apply a separate +12 volts to the pink wire, it goes to 12 volts on its own when not grounded.

I still have an issue with the driver's door, as it was not lowering or raising the windows when the release buttons were pressed, window switch operates normally? what checks should I make ? ...

I hope you don't mind Imram, I am just compiling some information for this garage and want to use your excellent guide you made for faulting and acknowledge it is your work here at Pisotonsheadshttps://www.pistonheads.com/gassing/topic.asp?h=0&f=6&t=2015699 . There is just one correction regarding where you say "Door contacts - check the inputs at the ECU, for continuity to earth between LH PIN (J45 B1) or RH PIN (J45 A1), upon closing the door. (its upon opening the door not closed )
No continuity to earth with the door OPEN (not closed) - should be followed by testing the door sensor with a magnet (with door open)...

Edited by Marty19671 on Friday 24th February 13:48

[Imran999]

Thanks Marty, I will update my original post with the details you have confirmed.
I had actually suspected that the alarm input would be the same logic as the other inputs (held high with a resistor to 12V and requiring a ground to switch the input) - thanks for confirming this.
Hope you get it all resolved, it does all work quite well when fully debugged :-)

Edited by Imran999 on Friday 24th February 17:18

[Marty19671]

I got to go back to the TVR tomorrow hopefully for the last time,as I twisted my back working in the back last time.

When I left, there appeared to be one issue left to deal with (possibly plugs or broken connection) which was the driver's window was not lowering when the release button was pressed, but opened the door and not raising when the door was closed. The electric windows via their switch, appear to work the window normally. The passenger door works normally.

I am not totally sure of the correct operation for testing

You said before the button on the bottom of the wing mirror triggers the Door Control Box (A7 orange) to drop the window slightly and then triggers the actuator that is connected to the mechanical mechanism on the door and when you shut the door the magnetic sensor in the bottom of the door triggers against the magnet in the sill of the body( in my case it is a 2 wire Pin door switch fitted), and this triggers the Door Control Box to raise the window at that point.

I am yet to test yet, but it would be really helpful to understand what to be looking for straight away, I am sure both the inner and outer door release switches must be working if it opens the door, but the driver's window is just not lowering or raising when closed. If you lower the window manually, it does not raise on its own when the door is then closed.

Do you think it is just the pin switch (magnetic contact) white/purple (A1) wire that could be causing all these problems of either not switching to earth when the door is open, (earth wire side from the switch broken or white/purple), or the connections are broken?? or would the limit switch(A2 blue/yellow ) affect this somehow if this wire was broken, as I am not sure of how and when it works, I assume the window would normally lower about 5" when the release button is pressed until it hits the limit switch where the blue/yellow (A2) from this switch wire gets grounded or does it go open? so what can be stopping the lowering?

Edited by Marty19671 on Monday 27th February 09:45

[Byker28i]

Have you cleaned all the contacts on the plugs inside the door. These have a real issue with dropping voltage when dirty and need cleaning every couple of years - well on my car anyway. Usually it's slow windows, but I've also had issues with the glass not dropping.

[Imran999]

You can test things with the door open if you have a small magnet.

With the door open and a magnet against the reed switch, press the button under the mirror and see what happens, it should lower the window and activate the door release actuator.

[Marty19671]

Thanks both of you, i hope not to remove the door panel if i have to as was only called out to fit the alarm , but have ended up sorting out the electrics with the knowledge gained thanks to you guys.

Its a pin switch fitted on this vehicle not a magnetic reed switch , but should be able to do the same test. Can the limit switch affect the windows lowering?

[Imran999]

You can test things with the door open if you have a small magnet.

With the door open and a magnet against the reed switch, press the button under the mirror and see what happens, it should lower the window and activate the door release actuator.