Very early glow plug wiring

[Napalm00]

I have an extremely early truck that has what could be a series style glow plug resistor. I've never found these on any wiring diagram and I've never seen another one.

It does work but only provides lower voltage to the plugs not the full 12 volts.

I thought about adding the TDI relay but really have decided to just use the intermediate position on the ignition switch.

I do need some help identifying these three connections If anybody has ever seen it.

big brown/red is obviously power from the switch.

Little brown/red that has a broken connection I have no idea what it does.

And white with blue or slate with blue I'm thinking should go to the bulb but it's not on any diagrams and it's never functioned in my truck.

Insight?

 

[Napalm00]

Well after using some further research myself it turns out I do have a late series 3 bulkhead harness. This is a first model year defender truck and I found all sorts of weird stuff on it that was holdovers from series manufacture.

Turns out this is one of them and also why I don't have wiring for a diff lock light. Because it didn't exist on a series truck.

 

[Napalm00]

Glow plugs are #3 in this diag

 

[O2batsea]

If you add a glow timer relay you will delete the curly wire resistor. The relay has connections on there for the dash lamp. Dash lamp is the white blue and the brown red.

 

[Napalm00]

Okay well it looks like I figured out the glow plug wiring. to make it work in the simplest way if possible connect the big brown with red stripe directly to the glow plugs AND Connect the small brown with red stripe directly to the glow plugs.



The white with blue stripe gets grounded.



This way when the circuit is activated the light illuminates only when the glow plugs are getting juice.



I don't really know how the series wiring setup functioned but it is definitely different than the defender gauge cluster.

 

[RBBailey]

I just built my own circuit through my auxiliary fuse block, a Carling momentary switch, and a solenoid. I could have hooked it up to the glow plug light, but....

 

[Napalm00]

Oh yeah I totally appreciate your input. I'm just trying to make this as simple as humanly possible I want the least amount of components in my truck.