Defender TDCi Puma 90 - Diff Lock Light

Morning All

My 2010 Puma Defender 90's diff lock light isn't coming on (it used to work). Following has been checked:

- The diff lock is definitely working.
- The diff lock switch is working (removed and tested).
- All fuses are good.

I've shorted out the switch wiring at the diff socket end and the light still isn't coming on. From what wiring I can access it all looks OK. So I guess there is a wiring fault somewhere between switch and dash but just wanted to see if anyone has been in the same situation.

Cheers

Rob

I am guessing a simple 2 wire switch has 12v 1 side, earth on the other. it doesn't matter which way it goes through the switch./lamp.
So do you have 12v or earth on the plug?
It does sound like wiring but where?

J

marjon said:

I am guessing a simple 2 wire switch has 12v 1 side, earth on the other. it doesn't matter which way it goes through the switch./lamp.
So do you have 12v or earth on the plug?
It does sound like wiring but where?

J

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Good point.....I hadn't checked the voltage. Have done now and am getting 12v at the diff socket. Still no joy though.

The switch on the LT230 simply goes to ground, there shouldn't be 12V at the switch (on the t'fer box), the 12V is on the dash lamp. Difflock on, closes the circuit and the lamp lights.

miktdish said:

The switch on the LT230 simply goes to ground, there shouldn't be 12V at the switch (on the t'fer box), the 12V is on the dash lamp. Difflock on, closes the circuit and the lamp lights.

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Which means 12v is earthed when the switch is closed so how does the 12v get to earth?

J

crashmat said:

Good point.....I hadn't checked the voltage. Have done now and am getting 12v at the diff socket. Still no joy though.

Click to expand...

So run a short wire wedged in the plug to earth and see if you get a light, it narrows down which wire is the issue and it sounds like an earth issue (which is usually always the case with a defender).
So where does it earth?

J

marjon said:

So run a short wire wedged in the plug to earth and see if you get a light, it narrows down which wire is the issue and it sounds like an earth issue (which is usually always the case with a defender).
So where does it earth?

J

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Did this from the plug straight to the battery -ve and still nothing. Looks it's the +ve side to the speedo/light unit in which case I think I'm done. I may well test with an LED and if that works look into embedding into the L/H lever to replace the dash light.

crashmat said:

Did this from the plug straight to the battery -ve and still nothing. Looks it's the +ve side to the speedo/light unit in which case I think I'm done. I may well test with an LED and if that works look into embedding into the L/H lever to replace the dash light.

Click to expand...

Do you have any other dash light issues?
If you have 12v at the plug it must earth through/via the light?

I fink @Wimblowdriver may have some wiring docs that may help perhaps.

J

Well worth a trot around this website, tons of useful info.

marjon said:

Do you have any other dash light issues?
If you have 12v at the plug it must earth through/via the light?

I fink @Wimblowdriver may have some wiring docs that may help perhaps.

J

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I have checked all of the other lights on the Speedo Unit (Fog Lights & Heated Rear Window) and they're both fine.

marjon said:

If you have 12v at the plug it must earth through/via the light?

Click to expand...

I though that was how it worked on mine but I have an '89 vehicle with a 300tdi wiring loom. I have two wires at the switch so assumed it went back to the dash rather than just earthing through the switch.

dag019 said:

I though that was how it worked on mine but I have an '89 vehicle with a 300tdi wiring loom. I have two wires at the switch so assumed it went back to the dash rather than just earthing through the switch.

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I am only working on logic.
2 wires, 12v an earth make a lamp light, which way the 12v goes doesn’t matter.
Which end it earths in this case I don’t know. But sounds like at the dash or wire too in this case, So continuity checks needed and dig in the dash.

J