4trak Glow Plug Relay - help please


I know this has been done to death before, but I have a problem that I don't think has been covered yet!

I have a 1993 on 2.8td engine in a 1971 Land Rover, and have been slightly confused by the previous owner's interpretation of good wiring on many counts!

My glow plugs are connected to the relay in a way I can't fathom. I have a battery connection going to a momentary switch in the cab. This goes to the big blue relay on my baulkhead. One other connection is switched, and the other two in the 'standard' relay part aren't connected at all. Then I have another connection from the battery that goes to the big bolt on the relay. The smaller bolt is connected to the busbar at plug number 4. There is also another connection on this that goes to a second relay.

This second relay appears to be connected only to the warning light on the dashboard. This all seems a bit wrong!

There are no other connections to the busbar, and I'm guessing there should be another connection from somewhere to the plug no 3 positon.

The current configuration works, so long as I keep my finger on the momentary switch until one of the relays clicks off, but I'd like a more 'normal' system!

Could someone please tell me how it should be wired up, on a terminal by terminal basis (a picture or wiring diagram would be brilliant).

Secondly, there is an electrical connection in the gubbins that is the turbo. I've connected 12v to it and it clicks, so I'm guessing its a solenoid. Previous Owner didn't see the need to connect it up. What does it do, how should I connect it, and does it make much difference to the performance if it is connected?

Thanks in anticipation of some helpful answers!!!


first thoughts are if its

first thoughts are if its working dont worry too much... i'd guess you have a momentary switch cos there isnt a heat position on the key switch? perhaps the lr was petrol before the daihatsu engine was fitted. a diesel key switch should have a sprung heat position before the sprung start position. the battery lead to one bolt terminal and the 2nd bolt to the heater rail sounds right for the high current to the heater plugs. there should be a timer unit in the heater relay which is also conected to the heater plug rail, theres a black wavy bit between the third and fourth plug thats some sort of temp dependant variable resistor which determines how long the plugs energise for before a cold start.. it should be a case of holid the momentary switch closed until the warning light goes off then turn the key to start... with the standard daihatsu wiring bthe glow plug relay will click in and out a few times after a cold start.. its supposed to make the cold engine run a bit smoother, i wouldnt be surprised if thats not happening on yours though.
it was all a lot simpler when you just had a simple push switch and standard relay and just held it in a bit longer on a frosty morning

Thanks for the advice

Thanks for all your answers - much appreciated!

The landy was born as a petrol, but had a Landy diesel engine wiring loom put in and hacked when the Fourtrak engine went in.

I thought the 'right' way to wire the glow plugs might have been to set it up to be ignition switched - I didn't realise that there was a particular key position for them. I'll probably just leave as is because it works fine, and the engine isn't too lumpy when cold.

I'm still a bit unsure about the electrical connection to the turbo though - it's definitely some sort of solenoid. I guess I'll just feed the battery to it and see what happens!

Thanks again for all the answers,

i would guess youve got a

fourtraks have a light in the rev counter that comes on when the turbo is blowing.. the conection on the turbo could be for that.


Ideally scrap the lot and begin again, the Fourtrak plugs come in two voltages, 7.0 volts and 7.5 volts, check the correct plugs are fitted.

Source an original Fourtrak glow plug relay, wire this to the original wiring diagram, but if the vehicle was a petrol conversion it will not have the plug heating position on the ignition switch.

Replace the heating position with a push button switch, this will be manually operated, but correctly wired and will supply the correct voltage to the glowplugs, and have temperature feedback control.