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MG Car Repair/1972 mg wiring


QUESTION: was checking fuses because my wipers were not working found bad fuse. but some how messed up my fuel gage doesn't work and my tack and my blinkers all stop working. and all worked before i played with the car. is there one fuse that controls all four things tack, blinkers,and temp gauges,and gas gauge.
         thank you Jim


Yes, there is one fuse that feeds everything that you have listed.  Fuse #3, which can be recognised by the GREEN wires coming out of it.  On a 1972 USA spec MGB the green wires feed all the following:

Brake lights, temperature gauge, fuel gauge, reversing lights, turn indicators, hazard flasher unit & rev counter.

The contacts of the fusebox may be corroded.  If so, you can clean them with electrical switch cleaner.  

It may also be necessary to clean the contacts on the WHITE side of fuse #3 as well.  

If the clips holding the fuses have lost their springiness then this will cause repeated problems, in which case it would be better to replace the entire fuse box.  

---------- FOLLOW-UP ----------

QUESTION: and if the fuse is good can something else cause the problem. thank you Jim

Hi Jim

If the fuse is good then the problem could be due to corrosion or a bad connection or a broken wire.  However, everything was working OK until the wipers stopped.  

As a test I would temporarily fit a jumper wire to bypass the fuse completely.  Put one end underneath one of the White push-on terminals and the other end underneath one of the Green push-on terminals.

If that checks out ok then I would check out every accessory on the list I gave you.  There are 3 green wires that all share the same fuse, so it would narrow down the search if some items were working and others were not.  

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Barrie Jones


MG Sports Cars from 1949 to 1980 - Including MGB, MGBGT V8, TF1500, TF, TD and modern Midgets. I also specialise in SU carburettors, Lucas wiring, suspension, steering & brakes.


I have owned my 1955 TF1500 since 1966. Technical specialist for the TD and TF with the MG Car Club T Register. Also owned 20 MGBs and currently own an MGBGT V8. Written 3 books on MGs and produced a DVD on how to strip and rebuild the TD/TF gearbox.

MG Car Club.

Barrie's Notes on the 1953-55 MG TF (author). /=====/ Barrie's Notes on the MGB (author). /=====/ Barrie's Notes on the MGB GT V8 (author). /=====/ The Essential Buyer's Guide to the MG TD, TF and TF1500. (author)

M Phil, C Eng, BSc (Eng).

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