6 replies to this topic

[timhodson]

Hi Everyone

 

I have a 1973 850cc saloon. I don't know too much about it but I bought it probably about 15 years (garaged) but have hardly ever driven it due to various issues. I'm not sure how original it is. I bought from a friend who had had it garaged for about 10 years before I had it (he had it as a part exchange).

 

I had the brakes replaced a couple of years ago and noticed that there had been mice living behind the windscreen wiper motor. They had chewed through some of the wires that were attached to the interments and gauges.

I bought a new wiring loom and thought I'd have a go at replacing it.

 

I am very much a beginner but learning fast, I think that I have followed this advice on here on how to troubleshoot/fix any issues.

 

Problems: fuel and temperature gauge not working. lamps behind temp gauge and oil pressure gauge not working (not too bothered about these but happy to take advice if it is an easy fix).

 

What I have tried: Fuel gauge - I have connected the two wires together at the fuel sender, no change to fuel gauge. I have performed a continuity test on green and black wire - this was fine.

 

Temp gauge - I have tried shorting the sender wire to the block but the gauge did not move. I performed a continuity test on the old sender wire which goes onto the dash before I connected it to the new green and blue wire - this was fine.

 

From what I have been reading on here it sounds like I need a new voltage stabiliser (Smiths instruments thankfully) but I just wanted to check that I am not missing something obvious.

 

If anyone can give me any tips on something I may have missed or confirm my suspicions then I would appreciate it.

 

Thanks

[GraemeC]

Check you have an ignition fed 12V supply going into the voltage regulator first (white wire - check with multimeter or test lamp).

Also check you have 12V to the illumination lamp on the gauge.

[timhodson]

Thanks for the reply GraemeC. I wondered what the white wire was for on the loom that I bought. I looked into things a bit more and it looks like it’s probably had an engine change at some point. I couldn’t work out why my 1973 850 had a temp gauge but it wasn’t on the pre 1976 wiring diagram in the manual.

I have two green wires that I think connected to the B terminal on the voltage stabiliser which makes me think that I have an old wiring loom (only an assumption, happy to be corrected).

If my assumptions are right is there a way to get these two gauges working fairly simply? I’m not too bother about the temp gauge but I would feel more reassured if I could get the fuel gauge working.

Thanks again for your help so far.

[GraemeC]

Apologies - it is a green wire as it is a fused ignition supply.  Is it live when the ignition is on?

Is everything earthed?

Edited by GraemeC, 26 May 2020 - 02:30 PM.

[timhodson]

The two green wires are joined into a single spade connector which measures 11.66v whilst the ignition is on. I’m not sure how to check if everything is earthed. If there is a thread you could point me to I’d be happy to give it a read.

Thanks

[GraemeC]

OK - if the green wires are reading 11.66V on the B terminal, what is the reading on the I terminal?

 

Easiest way to check for earth is a) presence of a black cable connected and b) check for continuity between the gauge case and a bare metal part of the bodyshell.

[timhodson]

Approx 11.5v on the I terminal. I think it’s all earthed. I have also just renewed my insurance so I am going for a little test drive. Fingers crossed.

Thanks for your help so far.