In my 94 w124 e320 I removed, cleaned, and painted all of my calipers last week. After re-installation the brake pad wear indicator light is on. Last night I attempted to trouble shoot the problem by unplugging all the sensors at the connection on the caliper. To my dismay the light did not go away with all of the sensors disconnected. I found the cause of the light to be the connector that bolts to the (front only) calipers. Without the connectors bolted into place the light is off. As soon as the connector is secured (ie. touching the caliper) the light comes on. Upon further examination it appears that when the connector touches the caliper the light comes on. Can someone tell me how this circuit is suppose to function? Is there suppose to be an insulation washer between the connector and the caliper? It only seems to be affecting the front calipers at the moment.

TIA

Whenever any part of the sensor wire circuit is grounded to the vehicle, it completes the circuit and turns the light on. From what you describe, it seems like the connector is completing the circuit to ground and is your problem.

__________________
Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record

So is there suppose to be a insulating washer between the connector and the caliper. The part i'm talking about is pictured here:

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Any ideas? I'm confused as I didn't think that the retaining connector touching the caliper was a problem.