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MG MGB Technical - lost turn siganals gas gauge the tach tetc

changed the distriuter cap and ppoints now no trun signals gas gauge temp gauge hazards the clock the fan etc. help is there a fuse?
1978 MGB
earl halle
new port richey fl
eb123halle@aol.com

thanks for some help
RE HALLE

the headlights and brake lights work
where is the phyical Tachometer located ??
thanks forgot this info
RE HALLE

I don't know which fuse (physically) covers those items, but it is the fuse for the green circuit. Check the fuse with a multimeter set to read ohms (don't use the MK I eyeball - it is a very poor diagnostic tool for fuses. You could also have a loose fuse clip on the fuse block. Cheers - Dave
Daved DuBois

when is the "green" circuiit. i an a raw amutur at this stuff thanks for the reply
RE HALLE

"when is the "green" circuit"
Look at the wires coming off the fuse block. There should be 4 fuses, one of which has a white wire coming to it and several green wires going off the other end of the fuse. The green circuit is switch, fused 12 volts. You can see this better by going to http://www.advanceautowire.com/ click on Stock Schematics and then on MGB. Scroll down to the year of your car and enlarge the print so that the colors show up. You should see a fuse being fed by a white wire (switched, unfused 12 volts). The other end of the fuse will have green wires on it - that is the green circuit (switched, fused 12 volts). Cheers - Dave
Daved DuBois

"now no trun signals gas gauge temp gauge hazards the clock the fan etc."

Do you mean the hazards and the clock don't work either? If so it's nothing to do with the green circuit as they are powered from the brown (hazards) and purple (clock). You mention 'fan', is this the heater fan or the cooling fan?

Does the engine run? Do the lights work?

A 78 should also have an ignition relay which complicates things as that introduces two separately fused green circuits. One of these has an in-line fuse which powers the cooling fan, and the other is the second fuse up in the main fusebox with four fuses. This fuse feeds most other ignition powered stuff except the ignition, fuel pump and overdrive.

Both of those are fed from the ignition relay, which also feeds the ignition. So telling us exactly and clearly just what does work and what doesn't will help us to help you.
PaulH Solihull

This thread was discussed between 07/11/2012 and 08/11/2012

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