Date: Fri, 21 Apr 2000 20:59:21 -0400 From: DRC <drcnopsamwa.com> Subject: Re: Brake lights not working
In article <ha9K4.54631$hT2.269716nopsam1.rdc1.ct.home.com>, "Dennis Dowd" <dowddennisnopsam.com> wrote: > I have an 89 9000S and the brake lights do not work. The bulbs are OK - > no > indication of a bad bulb on the pic-to-gram. I checked the switch at the > brake pedal and it looks OK. Any ideas - Thanks. > > > > Dennis, This happened on both of my brake lights on my '84 900. First the left assy, and a year later, the right. The problem was that the ground connection in the multi-pin connector that plugs into the back of the taillight assembly corrodes. Each time, it was the ground pin and only the ground pin that suffered corrosion. This interrupts the ground circuit to all of the bulbs in that cluster. The symptom of a bad ground is that the other lights in the cluster (running lights, back-up lights, etc) will come on dimly when you step on the brakes, since the current is taking a sneak path through these bulbs to get to ground, bypassing the corroded connection. The elegant fix - unplug the multi-pin connector (rectangular plastic with two rows of colored wires) that fits into the back of the taillight cluster. It is a very snug connector, and thanks to years of corrosion may be nigh impossible to pull out. If/when you do get it out, you can carefully remove the corrosion (which will be inside the connector on the mating surfaces between the plug and the socket). A liberal helping of silicone grase may be helpful in keeping out moisture and hence futre corrorsion. The inelegant fix (as practiced by my dealer): remove the cluster, as if you were changing the bulbs. Figure out which of the circuit board traces is the ground. It's the one that runs to each of the light bulb sockets. Drill a 3 mm hole through the plastic backing plate, close to but not through the ground line. Solder a 16 ga. black wire onto the ground line. Feed the wire through the hole you drilled and connect it solidly to a framing member in the trunk to get a new ground circuit.