temp indicator on a 73
 

i'm having trouble getting my temp indicator to work

can't seem to figure out the wiring on my car
the electrical schema is nice, but none of the wires match in colour

i pulled the gauge from the dash , and that didn't help much either
all the wires on the back of the clock , are just plain grey due to age , tried to clean em , but no luck , they are just too old
same with the back panel of the gauge, having trouble identifying markings

i did not pull the whole gauge out , because i don't want to disconnect the wires of the oil pressure , since that's one of the few indicators i have at the time



could anyone tell me , how the wiring should be
and what goes to what connector on the gauge?

if i get this, then i can pull some (temporary )wires from the back to the front
test things , and then see if it's the wiring or the gauge or the sensor that's giving me a hard time

rustle up the schematic on Pelican

The wire has green on it I think - maybe Grn/red or Grn/Blk

I'd check that sensor first. Stick a multipmeter on it and measure the resistance while the engine is cold - see if it changes when engine is hot.

Next, I'd take a look at the grounds...

I'd reserve gauge problems for 3rd. Ground the sensor wire and see if an asst. sees the gauge jump (ignition ON, right?).

Yup, you can run long wires outside the car....

At the guage:

Green/Red is oil pressure sender ...

Green/Black is oil temp sender ...


http://www.pelicanparts.com/911/911_..._CIS_Part2.jpg

thanks warren , if only my wires still had colour on them
they're completely grey

i'll see if i can pick em out in the back , on the main wire loom

if i understand correctly , the temp one should have 12 volt on it , right?

Both gauges have a 'multiple' from the unfused power at the bus connection for fuse #7 via the Red/Black wires.

bollocks!!

just investigated, found red/green but no green/black in the back of the car.. was hoping it was red/green , so i log on with the garage antique modem... and it's no good...

friggin black/green is not on the main wire loom

means i have to try the lot of em , and hope one of the wires is the good one...i so don't feel like running new wires... more to follow later on

this thing is driving me nuts

found the wire, it's a black one

there is about 6.5 volt current on the wire
if a hold it against the chassis , the gauge maxes out
i measured the sensor, cold it gives me about 1010 mOhm
if i pour almost boiling water on it , it goes to 250

sounds good right

not so

i connect everything
when i turn on the contact, the needle slightly moves
to 50C
but it does that regardless of hot or cold engine
so it doesn't mean jack

i drive the car for a good 7 minutes,
it's a sunny day about 70F inside more in the sun

nothing on the gauge
i let it idle for a good 4 minutes
still nothing

sureley the oil temp should be more than 50C by now!?
if i measure the sensor, it does read low resistance`

DUH !

turns out the gauge was working just fine
it was just my paranoia about overheating my rebuild

just went for a longer drive, and eventually the gauge does show a readout

also fixed the speedo, the idling is working fine now, and the flat spot is getting smaller and smaller. took it up to 110 mph... and ran out of road...once that flat spot is gone, it will go like stink !!!