2H Glowplug circuit

[Major60]

Looking for ideas on the following:

Glow plug lamp has stopped working and so to has the glow plug circuit. Vehicle starts OK if 12V manually applied to activate the glow plug relay. Glow plug controller correctly applies 12V to the glow plug relay under no load and with correct decay but drops to 0v under any sort of load (8W light bulb or actual glow plugs). So in essence the glow plug controller can not handle any load.

Changed the glow plug controller in the LH kick panel and still no go. Changed a cruddy looking fusible link from the main battery as well.

Anyone know what stops the glow plug controller working under load?

All other ideas welcome.

[SWAT]

Is the Alternater Light on the dash operating corectly?

The symptoms you gave discribed are sometimes caused by a failed regulator in the alternater or even the brushes

The timer has a input from the light to tell the timer when the moter is running

Chears Bruce

[Major60]

Alternator light working fine. And battery charger circuit also fine. Replaced the regulator (external type) as it was cheap and quick but still glowplugs still not working so I am thinking of the alternator as well. I guess there may have been some sort of input from it to the circuit. Will try that next.

[SWAT]

I would look at the glow temp sender // dose not sound like it would be the alternater

[-Scott-]

Your glow plug controller must have an input connection: where 12V comes in from the battery. It sounds like this connection has a high resistance ("bad") joint - when you're not drawing any current there's no voltage drop and everything looks OK. As soon as you try to draw any current, all your voltage is being dropped across the bad joint.

Check where the voltage comes into the controller when you try the load test - see if it drops to zero volts too.

What happens to your headlights when the glow plug circuit is dying? If they're OK it's unlikely you have a battery/alternator problem.

Either way, clean all the connections in the glow plug circuit, from battery to glow plugs. It won't hurt them.

Cheers,

Scott

[SWAT]

Good Call Scott

Chears Bruce

[Major60]

I had already checked the operation of the temp switch and it was fine. However last night I took the plug off and shorted the connections, still the same and glow plugs didn't fire. Then I accidently shorted the wire I used to short the plug out with onto the engine and everything worked!!. So now I know the problem is in the temp switch circuit. Off to Toyota for a new temp switch.

Thanks for the ideas.