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MG MGB Technical - Headlight Switch

Just spent Presidents day sorting out a headlight problem. I'm not looking for help, just passing on what i found. 1972 MGB. side lights worked, main beam worked, but switched to dip beam and the whole lot went off. Checked the wires to the lights, all connections good. Fuses working, but again with the help of a test light i found no power to the fuse with dip beam. It must be the switch i thought. Getting those things out is a real pain. Anyway, test light out again. Yup, no power to the dip beam. A new switch seemed to be the answer. But i was able to take the swich apart and found that the metal (copper/bronze)piece that slides over the contacts for side, dipped beanm was slightly bowed so that when pushed to the top (dipped beam position) it no longer made contact so no dipped beam, Ah ha. Bent flat and now it works fine. Cost zero, pride million dollars, anybody this might help priceless.
G.L Lodge

GL, Yesterday I had the exact same problem and fix on my MGA's hightlight switch. I could wiggle the switch and the lights went out. After taking apart and bending the contact, now works great...
Scott

I remember performing a similar repair on my 73B's headlight switch, but also noting alot of corrosion where the contacts mated the metal slider piece. Has me thinking that a relay in the circuit would take alot of the current away from that switch, and reduce corrosion/increase current flow to the lights...I know lots of others have done this with great success.
Erick Vesterback

Must've been the weekend for it.... My dips weren't working and I pulled things apart to see what was up. I found a similar problem to G.L.'s, fixed it - I thought - and put things back together. Turned out that wasn't the problem.

When I turned on the lights, a whole bunch of smoke got away and after some more searching, I found a place where some insulation and wrapping tape was torn, with corrosion peeking through. Apparently there were two problems - the first one kept the car from burning down. Ain't it fun?

R.
Rick Stevens

To help reduce some of the power draw through the headlight switch, Dan Masters has provided a wiring schematic for installing relays. He also has a headlight relay kit available on his site.

http://www.advanceautowire.com/headlight.pdf
http://www.advanceautowire.com/
Kimberly

This thread was discussed between 20/02/2007 and 22/02/2007

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.