no it's not erectile disfunction...

The fuel gauge and tempreture gauge on my Datsun 1200 (coupe dash) has recently started to read full alll the time even when disconnected! has anyone encounted this problem with there's?
and what's the solution...
It was reading fine untill this started happening.
Thanks for your help.

I had a similar thing with my aftermarket gauges. Turned out I needed another ground from the gauge to near the sender. Not sure if this helps.

The gauge calibration is controled by what we used to refer to a ballast resistor within the gauge circuit. Now I think it is located near the flasher unit on the peddel box. Small rectanglular alloy box with a couple of wires on it. I know that on my old Fords if these failed they would make the gauges read incorectly though I have never heard of your situation. I would try changing that unit first. I hope someone else can give you the correct name for it. I hope you don't have a problem with the circuit board as they can be expensive to replace or repair

The offending item is called a Voltage Regulator.
It is designed to supply a pulsed 12V feed to the Fuel and Temp gauges to compensate for temperature and voltage fluctuations.
It is usually a bi-metallic strip with a pair of contacts on it to interrupt the 12V feed.
You may be able to open it up and clean the contacts to repair it.
Nissan should be able to supply a replacement it you can't repair it

Dattofrog this does sound like a Ford instrument voltage regulator, my E250 Camper van just did this.

Now for the topic.........First step get out the manual and go step by step through the harness/gauge pack but is sure does sound like a some sort of regulator problem.

Tom

Disconnected? What have you disconnected?

If it's the battery lead that ypu have disconnected at the battery terminal & your 1200 model gauges still read full/hot then the gauges are now shot, but the cause would most likely be the instrument voltage regulator.

If the instruments really are showing full/hot with the battery lead disconnected, then a pre loved instrument cluster might be an economic proposition instead of replacing individual parts.

what i meant by disconnected, was I disconnected the fuel tank wire to see if it still read full and it did, I have been looking for the voltage regulater and no luck yet.. I will get out my manual and have a good look through the wiring diagram, thanks everyone for your help.

Quote:
See Re: Voltage Regulator (Instrument Panel) post in Main Forum.
Typically in DC indicating systems, a needle will ride high if it has a partial ground or, peg out when there is an open (no ground)

Hi Longbrow

Thanks for that. I have had a look at the tech section and it seems the regulator is the problem, I still can't seem to locate it... can anyone tell me where it lives.

Quote:

Salutations to you as well.
Please See Re: Voltage Regulator (Instrument Panel) post in Main Forum.
In the B210 "it" lives within the Water temp gauge.