Colin Symonds Posted July 23, 2022 Report Share Posted July 23, 2022 The fuel and temperature gauges on my 4a are lifeless, All of the rest of the gauges are working fine. I assume that the fault is with the gauge voltage stabilzer, so have ordered a replacement. My father was a professional car electrician, so I never had a need to learn, and electrics still remain a mystery to me. So, are there any other reasons that just those two gauges have stopped working? Quote Link to post Share on other sites
RobH Posted July 23, 2022 Report Share Posted July 23, 2022 If the indicators, wiper and heater fan are all working, there must be power getting to the stabiliser. That means it's either the stabiliser itself or a bad connection from it to the instruments that is at fault Colin, as that is the only common point for those two gauges. Odds on it is the stabiliser that has failed. Quote Link to post Share on other sites
Colin Symonds Posted July 23, 2022 Author Report Share Posted July 23, 2022 (edited) I've just checked and the wiper, fan and indicators have also stopped working as have the brake lights. The side and headlights are fine. Edited July 23, 2022 by Colin Symonds Quote Link to post Share on other sites
RobH Posted July 23, 2022 Report Share Posted July 23, 2022 (edited) Ok in that case check the fuse as they are all powered from the same one. (the one with white wires going to one side and green wires the other). Don't rely on a visual check alone. Do you have a voltmeter? The other possibility is that the feed wire from the fuse to the stabiliser has become disconnected. It is used as a common point to feed all those circuits If the fuse has blown and blows again on replacement, you will need to investigate further to find out why. The easy way to do that is to wire a small 12V bulb across the fuseholder with no fuse installed. If there is a short circuit somewhere the bulb will light when you turn the ignition on. (Pull the white wire off the ignition coil to stop it overheating while you leave the ignition on while doing these tests). Locate the stabiliser - it's on the back of the speedo I believe - there should be three green wires on the B terminal. One of those is the supply coming in from the fuse and the other two are feeds to the other circuits. Take all the green wires off and the bulb on the fuseholder should go out. Earth each of the green wires in turn until it lights again. That wire is the power in from the fuse - touch it to one of the other green wires. If the bulb lights that is the faulty circuit. Leave the faulty wire disconnected and put the other two back on the stabiliser. Replace the fuse and switch on the indicators, wipers and heater fan in turn. The ones that don't run are on the faulty disconnected circuit. Edited July 23, 2022 by RobH Quote Link to post Share on other sites
Colin Symonds Posted July 23, 2022 Author Report Share Posted July 23, 2022 Thanks for your help Rob, I'll check. I don't have a voltmeter, as I said electricity is a foreign language to me. I'll get some fuses and try changing it. 25amp? The wires at both ends look fine. Quote Link to post Share on other sites
Colin Symonds Posted July 23, 2022 Author Report Share Posted July 23, 2022 OK, I just cleaned all of the connectors on fuse box, I believe it is the original 1967 one, and reconnected the terminals and everything is now working. I do have a spare new fuse box, I think I'll change it over just in case. Thanks for your advice Rob, greatly appreciated. Quote Link to post Share on other sites
RobH Posted July 23, 2022 Report Share Posted July 23, 2022 (edited) I'm glad it was as simple as that Colin. If you do buy new fuses bear in mind that unless they are labelled with 'blow' and 'continuous' ratings you need to get lower rated ones. I believe you want "17A continuous / 30A blow" but only specialised suppliers sell those now. Most modern glass fuses from the likes of Halfords are rated only at the continuous current so you should get 20A ones to be on the safe side. Edited July 23, 2022 by RobH Quote Link to post Share on other sites
Colin Symonds Posted July 23, 2022 Author Report Share Posted July 23, 2022 (edited) Thanks Rob, you are a star. Any idea of a supplier for the 17/30 fuses? Edited July 23, 2022 by Colin Symonds Quote Link to post Share on other sites
RobH Posted July 23, 2022 Report Share Posted July 23, 2022 Sorry got that slightly wrong - its 17/35. Memory is going...... Green spark plug co. do them (ignore the writing on the fuse in the photo- they have used a generic one.): https://www.gsparkplug.com/durite-fuse-35-amp-blow-32mm-glass-pk10-0-374-35.html Quote Link to post Share on other sites
Colin Symonds Posted July 23, 2022 Author Report Share Posted July 23, 2022 Thanks. Quote Link to post Share on other sites
harrytr5 Posted July 26, 2022 Report Share Posted July 26, 2022 Had a problem with a mates TR4a and it turned out to be a bad earth due to a fully painted body shell soon rectified once I found it. The earth is part of the electrical circuit! Regards Harry Quote Link to post Share on other sites
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