fuel and temperature gauges fail with headlights on

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Luftmensch
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Location: London

Re: fuel and temperature gauges fail with headlights on

Post by Luftmensch »

thanks for the advice ... sounds like a good idea. (I think I can manage connecting the light gauge insulated wire, thanks your your offer though).

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AngeloEvs
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Location: Upwell, Norfolk

Re: fuel and temperature gauges fail with headlights on

Post by AngeloEvs »

I should of read the entire post, I assumed the regulator had a metal tab and that for some reason your normal ground connection for it via the securing screw was suspect. I cannot see in your posts any test to measure the voltage of the original regulator and, from what you describe, I don't see this as a regulator fault but standard 10V TO220 regulators are plentiful on EBAY, cheap and have metal tabs. The orientation regards Vin and Vout legs is still the opposite to the original TCY900 but placing a small nut under the tab will give you the ground connection as normal.

With the dash cover removed, it is reasonably easy to measure the voltage to the temperature guage with a multimeter (set to 20V DC or whatever range your meter offers that is above 12v) by placing a probe on the centre nut of the temperature guage and the other probe on one of the securing nuts to the side of the centre nut. With a cold engine it doesnt really matter which nut you use with the centre nut providing 0v.
1987 DG Karisma LPG with remodelled interior

Luftmensch
Registered user
Posts: 24
Joined: 11 Oct 2018, 10:39
80-90 Mem No: 16738
Location: London

Re: fuel and temperature gauges fail with headlights on

Post by Luftmensch »

You’re correct in pointing out that I had not actually tested voltage using a meter, since, as I mentioned toward the begining of this thread, that I had no experience using the thing and was hoping someone could walk me through various testing procedures. I did take your advice regarding the grounding of the regulator to the earth point at the temp gauge. In any case, even prior to this, I had been noticing - on longer drives - that the temp gauge now actually does register and the fuel gauge now works as well, even with the lights on. However, it does appear that the both gauges might be reading a bit lower than their intended settings since the fuel gauge reads 3/4 tank when the tank is filled to maximum capacity and the temp gauge might be registering a little on the cool side. Perhaps this regulator is calibrated differently. I’ll do the meter test you recommended and report back. Thanks.

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