Hi everyone,

I have a very strange problem that I am trying to troubleshoot.

It's about an oil temp gauge, to make this easier to explain, let's forget about the sender and signal. Only the +12V and ground of the gauge.

When I plug the gauge directly on the battery or on a computer PSU, it works.

When I plug the gauge inside the car (tried cigarette lighter, radio connector B120, even illumination), the gauge goes to max.

Does anyone recognize this problem? What's the difference between the 12V of my battery/pc psu and the 12V inside the car.

Ofcourse, plugging the sensor doesn't change anything on my 12V problem situation.



Thanks in advance,
Ben

 

Tried reversing the connections directly from a battery? Does it now go to max?

If so, try reversing + and - at the car connections...not on the car, obviously, but to the gauge.
Then report back pls.

 

Hi. I die wat you told me. So the 12v on the negative terminal of the gauge and the ground on the 12v terminal of the gauge. Doesnt go to max.

Now when I plug it normally it doesnt go to max anymore.

Will it work Now? What was the trick?

 

No trick, I was just wondering if that was the problem, since it DIDN'T go to max with a straight 12V.

Hope it's not b*ggered it.......

What make of gauge?

 

type-r ebay el cheapo brand, but that doesn't matter.
Why does it work outside the car and not in the car with both only 12V.

 

It can ONLY be reversed connections.

Have you tried a cable from battery of the car, direct?

I mean...12V DC is just that......

 

yes from the battery of the car it works ...
the question is, what is the difference between the 12v of the battery and the 12V inside the car

 

No difference, how could there be?.

Are you CERTAIN that what you have inside the car is 12V DC+ve and 12V DC -ve? You are CERTAIN which is the +ve?

To check use a test lamp, simple bulb on pair of wires, touch one end of one wire to an earth, the other wire to what you think is the +ve.

Or use something like this: http://www.ebay.co.uk/itm/6V-12V-24V...item4625ed349c

http://www.ebay.co.uk/itm/6V-12V-Aut...item3a9f95f547

 

My multimeter tells me +11.6V indeed

 

Between the supposed live and what?

I'd NOT trust a multimeter to find a +ve. sorry.

 

Always use m multimeter for this. Granted its not your average Joe 20quid jobby