Brake pad wear sensors

[mcbonio]

Trying to figure out it the e30 needs one brake pad wear sensor for all wheels or 1 for front and 1 for back.

I can't seem to see where the front pad sensor plugs in... I know the rear one plugs in on the offside of the car.

[Jozi]

Just two are needed, one front one rear. I can't remember which side the front goes on but I think it's the opposite of the rear.

[mcbonio]

Front near side? Where is the plug for it? Inside the engine bay like the ABS sensor?

[Brianmoooore]

Plug for the pad sensor clips onto a bracket on a tang at the top of the LH front brake backplate. There's no plugs and sockets under the bonnet, but the whole loom may have been pulled back in of course, or, if the car has fallen into the hands of a knuckle dragger at any time, may have been cut off.

[mcbonio]

Shall have another dig round, there is no loom there as I've just rebuilt the whole LH front leg of the car as some muppet fitted a non ABS hub to the car resulting in no working ABS.

As you say it might of been pulled in and 'looming about' in the engine bay...

[Jozi]

I'll have a look on my loom, I'm nearly sure it's a round black plastic plug your looking for.

[mcbonio]

Different sensor for the front and rear.?

[Brianmoooore]

Round white two pin connectors are ABS.
Sockets for the pad sensors are also round and two pin, but are black. The front left one is part of the main car body loom, and the rear right one is part of the fuel pump, etc. loom. On cars with drum rear brakes, there is a shorting link on the plug of the fuel pump loom, where it joins the body loom under the rear seat cushion, which simulates the missing rear pad sensor.

[mcbonio]

Cheers Brian,
On the front pad sensor loom, what colours are the wires? And should there be 2 or 3?

[Brianmoooore]

Wires are plain blue* and yellow/green. The wires tee off from the main loom about 12 inches along the inner wing from the fusebox, and the branch is readily identifiable, because the outer sheath is rubber rather than PVC or loom tape.

*connects to a blue/green in the main loom, near the branch.

[mcbonio]

Ok so just went in to my garage to have another scout around, and low and behold I'm presented this....

I know its not blue and yellow/green but it's the only 2 wires in a rubber sheath. Could that be my missing brake pad sensor loom?

[Brianmoooore]

That's almost certainly them. Doesn't bode well as to what you might find in the rest of the car in my experience.

[mcbonio]

Normally you'd be right, but its the only mechanical issue the car had really, It's not ideal but I got it as the shell is rust free. Plus I've not seen an e30 thats not been meddled with yet.

It does seem some 'knuckle dragger' has worked on the front left leg of the car. When I got it the wheel speed sensor on the leg was cable tied up in the wheel arch as they clearly fitted a hub with no ABS sensor hole, no brake pad wear sensor or loom present, and it had a bad wheel bearing to boot.

I got a hub replacement of pacerpete and rebuilt the whole leg. Just need to sort the brake pad sensor out, most folk might not be bothered but the red light on the dash is enough for me.!

Can I test these wires? Will the brake light go out if I bridge them?

Thanks for all your help again Brian!

[Brianmoooore]

Brake warning light should go out if the two wires are shorted together.

[Jozi]

I'm just picking my loom apart and found the end of the pads sensor loom is joined to 2x normal wires right before the fuse box. If you don't ming picking all the tape of the loom as far back as the fuse box then you could join in a new wire there from a scrapper. I might have the cables on a old loom that was kept for the plugs if you want me to post them?

[mcbonio]

Oh that would be great Jozi.! I'll pm you.!