1987 740 gle electrical problem?

- G
- golgo13
  
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posted
17 years ago

Sun, Sep 10, 2006 12:04 AM

hi,

again, i turn to this extrememly helpful forum for help. it's a doozie...

just last night, i noticed that the bulb light came in my dash. it only used to come on when i hit the brakes (the third brake light on the rear window doesn't work). it the right rear tail light as well as the right front orange light isn't on (and one of the rear licence plate light). the light bulbs are fine. i checked the fuse under the ashtray (strange place to put a fuse box, but i digress...) and the corresponding fuse was blown. i changed it, and the new one blew immediately.

now, isn't it strange that the left side of the car functions without the fuse? or maybe left and right ones are on a different fuse, but i couldn't decipher the fuse box. the blinkers work fine.

does anyone know what might be going on? i think there is a short somewhere, but why only the right side?

confused, jun

- J
- James Sweet
  
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posted
17 years ago

Sun, Sep 10, 2006 1:08 AM

It sounds like the bulb failure sensor itself has failed, it's pretty common for the solder joints to crack in here just like happens in the fuel pump and overdrive relays. Thankfully it's pretty easy to repair them as new sensors are $$$.

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- Mike F
  
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posted
17 years ago

Mon, Sep 11, 2006 1:49 PM

Left and right are on different fuses. Disconnect the wires from the taillight and see if a new fuse blows. Then do the same for the front light. If the fuse continues to blow with both disconnected, then you need to start searching the wiring for a short. Pulling the bulb failure sensor will remove the wiring to the taillight from the circuit, so that would be a good place to start. Note there are 3 wires for running lights going to the taillights. One is for the left, a second does the right, and the third does the small side lights in the tail lights and the license lights. The first 2 go through the bulb failure relay, the 3rd does not. However the 3rd wire shares a fuse with one of the tail light wires, so there's only 2 fuses.