89 740 Wagon Standard rear brake lights

lkalloch · Post by **lkalloch** » 15 Aug 2008, 16:00

Back again,

I replaced the rear brake lights with new bulbs but they still aren't triggering when I depress the brake. Fuse problems? I'm not sure. What do you think?
thanks for the help!

Cheers,
Luke

himmelsm · Post by **himmelsm** » 15 Aug 2008, 17:10

Luke,
I no longer have the Chiltons manual for the 740. But, as I recall, the fuses were were well labled on the back of the ashtray of my '84. If you have never pulled a fuse to check it. It is easy to see the upside down U in the center if they are good. I assume that you checked the harness connections to the light holders for oxidation?
Himmelsm

lkalloch · Post by **lkalloch** » 16 Aug 2008, 09:24

I actually didn't check for oxidation. Honestly, I don't know much about it. What are some tell-tale signs and ways I could clean it up ? Thanks for your help!

Cheers,
Luke

Post by **MadeInJapan** » 16 Aug 2008, 10:16

Oxidation is discoloration....usually sort of a white layer...if bad, rusted. If corroded, especially with copper it will turn green. Either way, a small toothbrush and some electrical contact cleaner does well...all auto parts stores sell this. If it's bad or hard to reach with, an emery board (like the ladies use for their nails) bent to fit small areas also does wonders.

Post by **billofdurham** » 16 Aug 2008, 12:25

Fuse #4 covers brake lights, shift indicator light, trunk light antenna and door warning. If the others are working the brake lights should.

If the contacts are clean and fuse is good check for 12 volts at the light unit with a multi-meter or a test lamp. Also check for earth (ground) continuity at the light units.

If you don't have 12 volts at the light unit check for 12 volts at the brake light switch which is mounted just above the brake pedal.

Bill.