Quick question

[pwd95]

AAAllllrrrighttyyythennn... why does my temp gauge read 2-3 degrees higher when the lights are on
during the day the temp goes between 84 & 91 religiously.....up and down like a pendulum.......sign of an air lock?

Then in the dark when the lights are on it reads up to 95 ......which gave me a bit of a fright I must admit. But then, when I got home, I sat in the garage, with the garage light on...let it idle up to 95 deg with the lights and fan on.......switch the lights and fan off and the temp gauge goes straight down to 90/91

Your wisdom will be very gratefully accepted
Thanks boyos

[jmorgan]

84 to 91 the effects of the thermostat opening?

Sort of no help but bought myself a one of them temperature reader thingies from maplins, point and press for a reading which gave me a piece of mind as to what was hot and where because I didn't trust the gauge. Turns out it is sort of right.

And fitted a fan overide just in case.

[jeff m]

I would check your grounds.
Long peice of wire, crock clip each end.
Supply good ground to guage and other logical places.

[Ye Olde Wecg]

Wynn you are not alone on this one, mine does the same except only when the heater fan or cooling fan override is switched on. The light switch doesn't seem to effect it. Weird! It's only a very minor difference so I have never worried about it. I'm guessing it's down to a poor contact somewhere but with my elastic trickery skills I'd probably cause even greater problems if I tried to fix it!

[leorest]

Dodgy earth. You can use a jump-lead connected to the -ve battery terminal to go around and see which earth is bad. Try under the dash and also the engine block.

[adam quantrill]

I bet you also see weird things happening to the gauges when the indicators click on and off. And/or the courtesy lights. As I recall the earth for the dash is taken through the bonnet release cable - which, being steel, ain't so good.

I reduced some of my problems by running a copper braid from the engine block to the dash metalwork.

[badred]

Just what Adam said, Earth the dashboard to the chassis direct. saves alot of problems and takes only half an hour or so.

[350zwelgje]

adam quantrill said:

I bet you also see weird things happening to the gauges when the indicators click on and off.

I reduced some of my problems by running a copper braid from the engine block to the dash metalwork.

With indicator on, my volt-meter jumps all over the scale. And it is different if indicating to left or right! Rest is fine if switched on or off, no differences, with in all situations a rock steady temperature indication (about 90 degrees) that only goes up in traffic until fan kicks in so trust it.

Good tip to run an additional earth for the dash, will put it on the to do list....

Rob

[thegriff]

mmm my tachometer is fine when the motor is cold but when hot once it reaches 3000rpm it goes to zero!!! think i"ll try the suggestion of running a wire between the block and dash,can"t do any harm