TR7 drivers door light

[UKPhilTR7]

I have my drivers inside door that does not light up. The passenger side is all ok and lights up.

Does anyone know where i can look at to sort this out and get my interior door light back on? any fuses or connections i can check without taking the dash out and following the loom?

[skertonman]

Usually cruddy connections on the door switch on the A pillar, which the door closes against. That would be my first port of call, then the bulb before delving further.

[UKPhilTR7]

Cheers for that. I have checked the bulb and that is fine, also cleand the connection on the switch on the a pillar.

I got thte multimeter out and on the passnger side there is around 13 volts on the drivers side there is only about 5 v. I disconnected the connector that the drivers side door light cable goes into in the drivers footwell and that was also only reading 5.

I have a feeling that the issue is slightly further doew the line. Where i cannot get to it with out the dash out.

[FI Spyder]

It's most likely one of the connectors n the circuit. Not sure where they all are physically, you would have to follow the wires and see where they go to. A wiring diagram should show how many. The connectors are crimped on and what can happen is the copper strands can break leaving only one or two to carry the load. Very hard to see unless you look very closely. I had a connector have all broken but one going from the rheostat up to the dash lights (had no dash lights). I opened the crimp (no easy job) recrimped and soldered it. A corroded connector can also lower the volt enough so the bulb doesn't light. This is easier to fix as you just need contact cleaner and a tiny brush comes in handy. Happy hunting.

[skertonman]

Another place to check is where the wires actually go into the door, constantly opening the door will continually flex the wires, and possibly break 1 of them. Same happens on the wires where the boot lid opens.

[busheytrader]

My wedge has an earthing point close to the bonnet pull.......... Might be worth a look on yours.

The metal caps on the glass cartridge fusses can oxidise and prevent conduction, even though they look fine. (I had an old Merc which was a bugger for this). A clean with a plastic kitchen scourer will clean them up. I don't know which fuse you need to look for, removing the dash won't help you.

[spanner]

Some of the contacts inside the switching mechanism inside the lamp can be a bit hit and miss so worth checking that they operate correctly while you have your meter out
A smear of contralube on the terminals will also help

[UKPhilTR7]

I will have a look at all the earth points that I can and I had not thought about the switch itself. I will have to have a look at it and clean as best I can. It is a 5 pin plug, so getting it apart without braking it will be fun.

I really need to get my hands on a later UK type wiring diagram to help me track this issue down. Anyone got any for a 1980 UL spec 7?

[busheytrader]

Howard B on this forum drew up and posted a wiring diagram for a 1981 TR7 a while back.

https://drive.google.com/file/d/0B0OCjg ... Ffc2s/view

viewtopic.php?f=3&t=23777&p=242849&hilit=Wiring#p242849


My ageing Haynes manual has a comprehensive wiring diagram for a 1980 DHC at the back. In common with other layouts, it shows earthing points on it but it's up to you to find them on the car. There usually very close to the electrical item, I guess less wire equals less cost. I've just had to remove and refit my dashboard after replacing part of the loom behind it, I didn't see any earthing points behind it. The major one is close to the UK passenger's left leg. There's several black wires earthing there. According to Howard's diagram, the door lights run through the 50A fuse.......

[FI Spyder]

There are a number of electrical diagrams depending on UK/North America, year (I think sometimes called early, middle , late), carbed, FI. You will find the one for your car in a 1980 or newer version of OEM manual. You can find these in pdf form, you just have to make sure it's new enough to have the 1980 circuit. I wouldn't trust the one not in the OEM. You never know for sure if it's right or not unless you put them side by side in which case you would use the OEM one anyway.

[UKPhilTR7]

Thanks, I will have a look bland see if this can help.

I will also have to have a look at the earth points by the passenger foot well, as I did not know about them.

I think it is strance though how the one side is working g fine and the other is not.

[UKPhilTR7]

The funny thing is that now i am getting 13 v at the door wires, but still no light coming on.

[FI Spyder]

If you have 12V at the light and still not working that means you have no ground whether that be at the grounding point or a broken ground wire in between. By checking the bulb did you run a continuity check across either end contact? It shouldn't be open. Like fuses, bulbs can sometimes look good but be open near the contacts where it isn't obvious and the best way is to put a multimeter on them and not do it visually.

[UKPhilTR7]

I must admit that I am thinking more down the lines of a break in the wire. When I checked the volts it was with the multimeter pins in the ends of the cables. In saying that though after a bit the reading was all over the shop, down and then up. Nothing erratic and rather steady, but the reading was not constant. When I did start to undo the door switch on the driver’s side, the passenger side light went off, so I am thinking that this is OK and doing its job.

[busheytrader]

https://www.tr-register.co.uk/forums/in ... h_id=27898

Circuit Diagram that was recently posted on the TR Register forum.

Hope this helps.