MG MGB and MGB GT Tech Talk
I am at my wits end. My tach, wipers, heater and turn signals quit working. The wiring diagram shows the no. 3 fuse. I cleaned the connections and changed the fuse. Nothing. What could be the problem? I am thinking it has to be at the fuse but I have continuity there. All suggestions will be tried. Thanks.
Check the voltage stabilizer. It's under the dash attached to the firewall. three gn. wires w/ spade plugs to a little rectangle box.
PS if that is'nt it use your circuit tester and ck. continuity @ fuse box. Good luck.
I have continuity at the fuse box. Next the voltage regulator.
Norman, check to ensure you have 12V at the third fuse. From there your green wire should go to a four wire bullet connector. check there for 12V. That connector feeds votage to the items which aren't working.
http://www.advanceautowire.com/mgb.pdf
You say you have continuity at the fuse. Can you measure 12 volts at the green wires on the output of the fuse? Can you measure 12 volts when you turn on any of the accesories?
It is possible that you measure 12 volts at the green until you try to turnon any item that runs off the green wires. That would indicate a high resistance situation at the fuse block.
Like Paul says. We all have those moments when reading a post, "Yup, been there, done that"...
I had a similar problem years ago. Traced it back to the relay.
I just had the same problem. I had continuity but nothing worked. I decided to change the fuse anyway and in so doing I pressed the fuse in and everything worked. Later--nothing worked. Found the problem--the terminal for the fuse wasn't making good contact. When I pressed the fuse things worked but release and nothing worked. I changed fuse block and now everything works.
After using steel wool on all the fuses and connections to the ignition relay, I replaced the ignition relay with a generic relay for trailor lites that cost $7 at Advanced Auto. That fixed my problem, maybe it'll fix yours. Donno.
I think Carl and Dennis are on the problem. Can't hurt to try a new relay.