Front door open/interior light switches

Philip Chidlow · Post by **Philip Chidlow** » Thu Mar 31, 2011 2:28 pm

I'm getting through some of the wee joblets I have to to do on the BX estate and I have something I need advice on.

The interior lights work. They come on when I open the back or rear side doors, but not when I oen either of the front doors. Apart from the fact I thought both switches are unlikely to have failed at the same time, I gave them a clean and a wiggle to see if I got a flicker. Nothing. So I wondered if there was a fuse specifically for that part of the circuit? If not, what else should I be looking at?

Discoil · Post by **Discoil** » Thu Mar 31, 2011 2:43 pm

Do you have a 12 volt feed to the switches ?

Philip Chidlow · Post by **Philip Chidlow** » Thu Mar 31, 2011 4:14 pm

I haven't had time to get the old multimeter out, but that's next to do - I was just being lazy

mnde · Post by **mnde** » Thu Mar 31, 2011 5:25 pm

I've got a similar problem with mine that I've not been able to rectify for over three years now (except mine only has front door switches).

The lights come on when I open the passenger door, but not the driver's. I've taken the pillar switch out, checked the wiring connection, cleaned it, sandpapered it, but nothing! I can only imagine that there's a short or a break in the wire somewhere. But it's rather low on my list of jobs!

Mark.

Philip Chidlow · Post by **Philip Chidlow** » Thu Mar 31, 2011 5:29 pm

Mmmm. Well I guess I should be glad that the list I have at the moment is short - and this is up there with de-rusting the wheel bolt heads. lol

citronut · Post by **citronut** » Thu Mar 31, 2011 7:31 pm

these switch's dont have posative/live going to them, as all they do is conect an earth to the lamp/s,

if you pull them out and whilst holding the button in clean the matting surface's of the contact area with a piece of fine wet and dry,

the contact surface does become tarnished,

regards malcolm

Post by **mat_fenwick** » Thu Mar 31, 2011 8:16 pm

You're right in that it's a switched earth, but if you use a voltmeter to measure the voltage between the switch wire and earth, assuming the bulb is in place and not illuminated you will see 12v. Reason being the meter has a high internal resistance, so very little current will flow and there will be negligible voltage drop across the bulb.

Silicone grease on the contact surfaces will help prevent corrosion in the future. Good luck with the wheel bolts!

smiffy1071 · Post by **smiffy1071** » Fri Apr 01, 2011 4:09 am

mnde wrote:I've got a similar problem with mine that I've not been able to rectify for over three years now (except mine only has front door switches).

The lights come on when I open the passenger door, but not the driver's. I've taken the pillar switch out, checked the wiring connection, cleaned it, sandpapered it, but nothing! I can only imagine that there's a short or a break in the wire somewhere. But it's rather low on my list of jobs!

Mark.

Mark, you may remember I had a look at it for you at stratford last year, while Chris was doing your front wheel hub. There is no power to that wire on the drivers side, so you will need to trace where the wire goes under the dash.

NZ16v · Post by **NZ16v** » Sat Apr 09, 2011 3:14 am

Under the steering column cover is a combined earth plug- bunch of wires going to one big unit.

Check that some havent come adrift.

Also- check the back of the door-open unit itself. Some wires can come adrift.

Philip Chidlow · Post by **Philip Chidlow** » Sat Apr 09, 2011 11:42 am

I removed the switches, cleaned the contacts, screw and pin. Still no joy. So I 'twisted' from side to side the push switches a bit in placeand now they work a treat.