Door / Window drop sanity check

[tommobot]

Trying to pin down a window not dipping down upon opening the door:

In breif;

Passenger door works perfectly.
External door opening button works / internal door opening button works.
Window works up and down.
Interior light acts as it should, i.e door closed light comes on etc.. suggests 'reed' switch is working (B in photo?)

I've tested the window 'detector' switch at the front of the door with a mulitmeter, and think its functioning - The resitance changes when it is trigger, which would suggest its working. (A in photo) There was evidence of recent~ish fudgery with this switch, so potentially could be at fault, but would expect the window to still drop fully whislt looking for the trigger (unless its smart enough to realise the trigger is broke!)



As far as I can tell, all of the pieces of the puzzle are working correctly.

I've tried disconnecting the door ECU for 30mins or so, but doesn't seem to make any difference.

Also disconnecteed the door ECU and closed the boot (what a tt...)

Which leads me to think, that the ECU must be at fault? - I've opened it up and had a look to see any obvious damage but looks spotless inside..

Any thoughts, or input much appreciated!

[FarmyardPants]

The two main parts are the micro switch and reed switch, as you have already identified.

If the micro switch is apparently closed, that will stop the window dropping as the window ECU thinks the window is already down enough, so check that and its wiring carefully.

You can test the reed switch by holding a magnet against it (I can never remember whether it s on the door or the small recess on the body). That will fool the car into thinking the door has been shut (and will usually cause the window to go up and the courtesy light to go out after a couple of seconds).

I would check the micro switch first, eg disconnect it and when the door is opened the window should go all the way down (as the ECU is looking for the switch to close). You can also manually touch the connectors together to simulate the switch closing.

For getting into the boot you can message me directly through my profile.

Best of luck!

Edited by FarmyardPants on Thursday 23 July 13:42

[tommobot]

FarmyardPants said:

You can test the reed switch by holding a magnet against it (I can never remember whether it s on the door or the small recess on the body). That will fool the car into thinking the door has been shut (and will usually cause the window to go up and the courtesy light to go out after a couple of seconds).

I would check the micro switch first, eg disconnect it and when the door is opened the window should go all the way down (as the ECU is looking for the switch to close). You can also manually touch the connectors together to simulate the switch closing.

Edited by FarmyardPants on Thursday 23 July 13:42

Thanks for the reply, I've got into the boot now so one problem solved atleast!

I've pretty sure I played around and tried to bridge the wires to the microswitch wires, (it had been replaced previously and had spade connectors)...

I definetly didn't try to close the door with the switch disconnected though, so thats worth a try.

Is there a reset, or relearn 'approach' to get it to reconfigure itself, as to me atleast its looking like its the ECU box in the rear at fault..

[FarmyardPants]

Could be the ECU, let s hope not.

A few clarifications- what you have circled as B is just a connector, the reed switch/magnet is right at the bottom of the door. Sorry if I am stating the obvious

Also, you should not be able to put the window all the way up when the door is open. If you can, that suggests that either the ECU thinks the door is closed (implies reed switch/wiring/ECU) and/or the micro switch circuit is closed even when the window is above the switch.

If those spade connectors on your micro switch are touching one another then you will get these symptoms

Edited by FarmyardPants on Thursday 23 July 15:43

[tommobot]

FarmyardPants said:

Also, you should not be able to put the window all the way up when the door is open. If you can, that suggests that either the ECU thinks the door is closed (implies reed switch/wiring/ECU) and/or the micro switch circuit is closed even when the window is above the switch.

Edited by FarmyardPants on Thursday 23 July 15:43

Ooooo interesting, I hadn't considered that actually..

I've had the car less than a week, and the window didn't at all work inititially.

Door panel off, clean and check plugs and motor fired back up again.

I'll double down on it again, but your giving me hope!

[tommobot]

Still battling with this..

Door ECU was sent to Python Racing, and tested on another Cerb and worked perfectly, so i've got a fault somewhere.

I've double checked trigger switch, its definetly working (possibly backwards maybe???) but continuity is gained where switch is closed - either way its some sort of action when the window goes down but so would expect some action but theres no movement whatsoever.

I've ordered a replacement trigger swtich for the window to see if that solves it.

The interior light comes on when the door is opened, and closes when door closed, which suggests perfect operation.

Unless i'm missing something blindingly obvious here, i'm stuck!

Perhaps the magnety thing in the door isn't working, I guess it must be connected to the indiviudual door to know which side one to drop down... I haven't quite mentally worked out how its wired, but I thought it was just a manget in the door and body, but if thats electrically controlling the window dropping aswell as being a magnet then good chance of that being at fault? Maybe - TBH, just writting this out has made me think this out.. (Apoloiges for the rambling!)

[Tony91]

if the door opens but the window doesn't drop hold a magnet to the inside bottom of the door the window should drop then the magnet should be roughly in line with the door slam recess. lift out the reed switch and clean or replace the wire connectors. I replaced my reed switches at the same time as replacing all my door connectors as the are old open style so replaced them with modern connectors that are weather proof. As for the window limit switch its just a make and break miniture lever micro switch, Just use a multi meter to check it works . Most of my door problems were from corroded connectors.

[Byker28i]

I had to replace the magnet detector once, corroded wires and one had broken off

RS Components £10:15
https://uk.rs-online.com/web/p/magnetic-proximity-...

Part no. 455-3744, this switch can be NC or NO, TVR use Normally closed circuit, so ignore the green wire and just use the white (common) and the brown.

[tommobot]

I did test the reed switch, with the multimeter... Removed from door and held close to car and it produced closed circuit etc.. which would suggest functioning correctly..

I new window dropping switch should be here later today, so will fit that and see but I'm not holding out any hope... If thats not it, then will repllace the reed switch.

I have noticed that the door light coming on is triggered by the switch, as opposed to the door 'opening' but the interior light goes off correctly when shut suggesting correct function.

[Byker28i]

Still got the magnet?

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

and if you want a really long, detailed explanation of how it all works
https://www.pistonheads.com/gassing/topic.asp?h=0&...

[tommobot]

New window dropper switch delivered and fitted, and no change, exactly the same still - So I think new reed swtich will be potentially on order aswell, even though i'm 95% confident its not at fault but i'm really running out of ideas!

I've checked the junction next to the throttle, disconnected and cleaned and checked the trigger and reed switch wiring for continuity, and it checks out as intact.

I guess next check would be to try continuity from both switches back to the ECU in the boot...