I was doing some late night reading last night about the electrical system on these cars, specifically the instrument binnacle.
It turns out that the fuel gauge and temperature gauge both use the same voltage regulator and circuit. So, apparently, if the gauge is at fault it usually affects both.
My temperature gauge works perfectly so the problem is most likely either the wiring between the gauge & sender or the sender itself.
So today I’ve had a look. You know shits getting serious when you break out the multimeter!
A bit of testing showed some severe voltage fluctuations at the live wire at the sender connection. Looking into the connector showed it to be full of dirt and corrosion. Cleaned it all up and it improved but still no good.
Then I looked at the earth wire. This is a short length of copper wire that just connects to the senders earth pin one end then runs up through the boot floor to a clean patch of the bodywork inside the boot. The interior bit seemed ok, but the outside end, the connector was also full of crap and corrosion but closer inspection showed the outside half of the wire had gone green and powdery inside. Basically the earth wire was useless!
I’ve completely removed the old earth wire, and to be safe, chopped off the last inch or so of the live wire. Then soldered on a new length to the live so it’s the correct length again and put a new connector on the end. The earth wire I’ve completely replaced for new wire with a new eye terminal for the interior connection.
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Trying to connect the sender became a pain in the arse though. The live was fine, but the senders earth pin is a weird shape and size and of all the many electrical terminals and connectors I’ve got nothing would fit well enough to stay secure.
A bit of head scratching later I found an old single chocolate block connector, stripped off the plastic insulation then managed to slide the senders earth pin into one end and tighten it with the chocolate blocks screw, and the earth wires end into the other end!
Is it really a bodge if it works so well!?
You can just about make it out in the pic!
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So with everything back together I flicked the ignition on and was rewarded with,
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Thank fuck that was easy and didn’t result in me having to pull the sender out and drain the tank.
Then I thought I’d check the other electrical stuff at the back of the car which showed the number plate lights weren’t working.
This turned out to be the same basic problem. No earth connection.
These are earthed by the metal bulb holder touching the body but obviously won’t work if there’s paint between! Fixed by scrubbing a clean patch under the bulb holder and tightening the screws. Easy!
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That’s two irritating problems ticked off the list.
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