temp gauge

[jindle]

Anyone know if this is fused separately? Just drove it home along the m4 and the gauge didn't move, all the other gauges appear to have some life in then

[TVR RULES]

No. The temp guage should have its own seperate ground wire (double black),sending signal wire and ignition signal wire that go to that guage. I would gently pull the guage out to make sure that the wires are connected. Turn the key on, the guage needle should slightly jump letting you know you have a signal to the guage- use a multi-meter with a Vdc setting on the double green-I believe. If they are connected well, I would check the temperature sending unit itself with a multi-meter. Guages rarely go bad; it's usually a wiring problem. I had VDO stock guages and changed them, however, the connections are the same.

[jindle]

Thanks for the advice. Is it a case of gently prying the gauge itself out with a little screwdriver? I tried pulling it by hand but it didn't budge.

I'm fairly certain it is just a poor ground as the needle doesn't bounce up at all on the key turn.

I suspect to find a bit of corrosion around there as the dash lights do not illuminate past that point either.

[TVR RULES]

O.K. First, is it a VDO guage? If so, here are 2 very bad pics I took of my guage. First is the face of the temp guage. The readings go 40 degrees Centigrade to 120 degress. Second pic, and most importantly, is the back of your guage, also a bad pic, but here should be the connections. It's 3 pronged. The top of the 3 prong connector there is the letter "G"next to it. There should be a green with blue tracer wire connected to it. This wire gets a signal from the temp. sending unit on your engine. The bottom prong has a "+"next to it. A double green wire should be attached to this prong. This is the 12 Volt signal to the guage from the ignition. Lastly,on the left side prong is your ground wire. There is a symbol that looks like an upside down "T" next to it. There should be a double black wire actually 2 solid black wires together,connected to it. I hope this helps and forgive me for my bad photography. If yours is different, let me know. I think I can help.

[TVR RULES]

[TVR RULES]

You might have to use a small tipped flat screwdriver or a dull butter knife to wiggle it free, but it will come out,just be a little gentle. As far as the illumination, do none of the guages light? if so, the first thing to check is the fuse. There is a seperate fuse to illuminate the dash light guages only. The temperature guge had 2 wires that connect to the top of the back of the guage. There is a black plasic twist piece that inside is your light bulb. The 2 wires that connect to that black plastic connector should be a red wire with a white tracer (power) and a single solid black wire (ground). These 2 wires illuminated this one guage. Let me know.

[jindle]

Yes it is indeed a VDO gauge, so will give that a go tomorrow. Thanks a lot.

[adam quantrill]

First check the connection at the engine end and the sender resistance.

[TVR RULES]

Adam has a point. Find your sending unit on the engine. take the connector off. Cross the 2 terinals or find a ground, and check the sending units resistance values when the engine is cold. I believe the resistance will be high at first. Start the engine, as the engine warms the sending units ohm resistance values should go down. Simply,if the resistance values are the same no matter if the engine is cold or warmed-up,then the sending unit is bad. It's worth a try.

[jindle]

haven't had a chance to look at this thanks to the weather, but do you reckon the reason for my petrol gauge & speedo needles bouncing up and down erratically is going to be bad earthing? would certainly tie in with the non working temp gauge.

Edit: figured out why the gauge wouldn't come out though. Connections look pretty clean too. Bad earth or sender.

Edited by jindle on Tuesday 17th December 21:40

[TVR RULES]

jindle, your connctions on the back of your temp gauge look good. I would ohm test your temp sender. Also, your speedo is mechanical and works via the steel speedo cable that inserts in the back of the speedo. There is a threaded nut in which the cable passes through driving the speedo. This nut could have come loose. Check also, that the speedo cable is inserted squarely inside the back of the speedo. Your dash lighting situation, on the other hand, is electrical. There is a common ground that connects all the gauge lights in which there is a fuse; check that fuse first. I believe the headlight switch,and on mine, I have 2 positions---first,parking,dash turn on. The second position pops the headlights up lighted while retainig everything from the first postion. You might have to check the headlight switch on the steering column. I hope this helps!

[jindle]

Starting to fell like I'm slowly going mad. Only two gauges have non working lights, only the temp gauge had stopped working entirely and the head lamp pods don't currently popup on command.

Starting to think it's all connected. I blame Colin (the man who's name head been scheduled on the inside of the headlamp pods along with the car number).

Just need a day off to try and sort this all out!!!

Edited by jindle on Wednesday 18th December 23:59

[jindle]

Having finally seen daylight I've taken her for a very short spin. 4700ohms cold, 310 hot.

So most likely a bad earth, finding that will be fun I'm sure.

[mrzigazaga]

Hi Mate...It generally is an earth..Its one of the biggest issues with fibreglass cars..I have yet to locate them on my 350i as i haven't had her for long...The 280i had headlamp diodes/Earths on the support frame for the radiator and a big bunch of earths near the relay board...Just clean any you can find...Ziga

[jindle]

Yeah I've already cleaned up the ones by the radiator support (when I was trying too get the pods working.. they still don't)

Would take the centre console out to trace the wires but it's too cold outside.

[V8 Fettler]

Be prepared re: bodges by previous owners. I removed the dash on my 30 year old 350i last winter to make the speedo work; cowboys, previous, 4 separate earth faults immediately made their presence known. Fuel gauge still temperamental: vaguely accurate or panic, but I can lay the healing power of my finger tips on the wiring behind and all is well for another month or so. Bizarre.

Wouldn't happen with a Nissan Micra I tell ya. But then you wouldn't leave a warm bed early(ish) on Christmas Day to run a Micra up to 6k+ rpm on deserted roads.

[jindle]

Yeah I should probably buy some crimp terminals and heat shrink...