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MG MGB Technical - Loss of Highbeam

My highbeams just quit working. I get the blue light on the dash when I try and use the highbeam or flash them. The bulbs are good. Trouble light doesn't show any power coming to the highbeam lead on the bulb. Where should I start looking for the problem? Thanks!
Mike D.

Mike,
Since the high beam indicator is working, the most likely suspect is the blue and white wire that powers the 3-way bullet connector on the right hand side adjacent to the horn. It has either come loose or is corroded. With the headlights on and the dip switch in the high beam position, pop the hood and play with the connector on the right side. You'll probably regain your high beams. Stock, tired wiring can lose 3 - 4 volts between the switch input and the headlight socket. Increased resistance raises wire temp which expedites oxydation between poor connections, and causes arcing on switch contacts... Clean all of the headlight connections and you'll find a few extra lumens for the road. Better yet, go with a pair of relays fed by heavy gage wire from the B+ terminal on the starter and let the existing blue/white and blue/red wires control the high and low beam relays, respectively.
Mark Childers

ike, I had the same problem. It was the bullet connecters behind the grill. Apparently a common problem. Clean everything up or, better, replace the connecters.

Good luck,

Resh
Resh

Yep. WHen I bought my car, three years ago, the high beams didn't work. I began tracing the wiring. When I got to the bullet connector behind the grill, I simply disconnected it and reconnected it and, voila! Everything worked. Apparently, the connection had corroded and when I reseated it, this scratched through the corrosion and made contact. I then cleaned the connector properly and I have had no trouble ever since.
Paul Noble

Bullet connectors were the culprit!!! Disconnected and reconnected several times and the lights are now working again.
Mike D.

Replace the connectors, clean up the bullets with wire wool, and dip in Vaseline before reassembling for a more permanent repair.
Paul Hunt

This thread was discussed between 14/08/2002 and 15/08/2002

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