Not the usual coolant gauge fault - I've checked everything!

[cookbot]

Got my '89 van a few weeks ago and have just got round to having a good look at it (i'll introduce in another part of the forum)

As per the title, my coolant gauge is acting up. The gauge does its blinking light start up check, but after that the gauge doesn't even move, not even after a 6 hour drive Now, I've had it apart and checked the following things:

- I've changed the sender
- I've checked resistance of the red/yellow line to the dash plug
- Checked all the spring contacts of the plug and cleaned the exposed contacts on the pcb/ribbon thing.
- checked resistance on the ribbon between the contacts and the metal posts than run into the gauge unit
- cleaned all 3 threaded posts on the gauge.
- checked for bad earths
- checked the voltage regulator, which gives a clean 10v
- the gauge isn't physically stuck.

Does anyone have any more ideas of things to check or is it time to start hunting for a new donor dash? Shame really as everything else is fine with it!

Thanks in advance, Paul

[marlinowner]

Have you grounded the wire to the temperature sender? That should send the gauge to max.
If it does then sender is faulty.
If not, disconnect the coolant level sensor on top of expansion tank, turn on ignition. After a short time the red led on the gauge should start flashing. If it does then wiring between gauge and relays is OK, including the circuit board on the instrument panel. I then would suspect the gauge itself.

[tonytech]

What engine do you have.
DJs have two sensors. one for the engine management and one for the gauge.

T

[cookbot]

It's a 1.6 na diesel.

[cookbot]

Have you grounded the wire to the temperature sender? That should send the gauge to max.
If it does then sender is faulty.
If not, disconnect the coolant level sensor on top of expansion tank, turn on ignition. After a short time the red led on the gauge should start flashing. If it does then wiring between gauge and relays is OK, including the circuit board on the instrument panel. I then would suspect the gauge itself.

Sorry, ground which wire to earth, the coolant temp line? (red/yellow).

As for the level sensor, I'll have to go have a look what it does when it's disconnected.

Thanks, Paul

[marlinowner]

Yes the red/yellow

Should have said when coolant level sensor disconnected and ignition on, led should do initial flashing, go out, and then start flashing again shortly after.

[cookbot]

Yes the red/yellow

Should have said when coolant level sensor disconnected and ignition on, led should do initial flashing, go out, and then start flashing again shortly after.

Thanks, I'll go look in a bit when it stops lagging it down! If it is the gauge (which I suspect it is) has anyone ever found these for sale as a separate item, or will I be stripping clocks?

Thanks, Paul

[marlinowner]

There are two types of gauges, depending on whether or not you have a rev counter. They do come up on ebay etc every so often.

[cookbot]

Plot twist - on earthing the sensor line, the gauge lives! I've got to start poking around now! Maybe a bad earth to the engine? Maybe an airlock ar the sensor stoping it from getting a reading? Who knows. I hate auto elec......

Thanks for the help,

Paul

[cookbot]

Turns out there's nothing wrong with the dash, wiring or sender. I've just wired it up as a circuit and used a head gun - works as expected Got to figure out why the sensor isn't getting hot enough now. Duff stat, trapped air perhaps, who knows.

[cookbot]

[img]//images.tapatalk-cdn.com/15/06/14 ... 5d56fb.jpg[/img]

I have reason to believe this might not be letting it get to temp..... Grrrr. Sunday too, so good luck me finding one of these.