Cold Start Light

Still learning the ropes......

I've got a 'Cold Start Light' in the dash.

Wossit for and wossit do? (Haven't seen it light up yet).

Cheers

petrol series 3's used to have a switch on the original choke cable and used light up a orange cold start light to show the choke is on if a aftermarket choke cable is fitted usually this would be hanging behind the dash

Sorry...I should've mentioned the old girl is a diesel.

I thought the light would come on, whilst the glow plugs are on, then go off when at temperature optimizing starting.

Ermmm.....that sounds a bit too sophistimicated for an old Landie diesel!

You have to turn the key and hold against the spring after ignition on and just before the starter position and you will see the light start to glow and get brighter. Do this for 10 to 30 secs then turn the key all the way to start. It's unlikely to get cold enough in Oztraylier to need it though.

The light doesn't come on when the glow plugs are 'glowing'. Must be a bulb blown.

I normally need about 30 secs of 'glowing' before she'll start.

She doesn't like the cold, and it does get cold where I live. Jeez it dropped to 25 this arvo!

The light doesn't come on when the glow plugs are 'glowing'. Must be a bulb blown.

Click to expand...

It depends on your pre-heaters.
Are they original series type or the more modern parallel ones?
These drawings may help you decide....The wire colours are what I found under my bonnet but I think are standard.

If the old series type there should be a thick and a thin wire on each end of the balast resistor. The thin ones go to the cold start bulb....

With the parallel pre-heaters both thick wires and one of the thin ones need to be joined together (one end of the balast is a convenient point to do it) and the other thin wire needs to be connected to earth. the earth wire to the front end of the engine, that used to go to the front pre-heater, needs to be taken off.

It is not unknown for the newer pre-heaters to be fitted but the thin bulb wires get left in the old positions, this will stop the bulb from lighting.
Regards rog8811

rog8811 said:

It depends on your pre-heaters.
Are they original series type or the more modern parallel ones?
These drawings may help you decide....The wire colours are what I found under my bonnet but I think are standard.

If the old series type there should be a thick and a thin wire on each end of the balast resistor. The thin ones go to the cold start bulb....

With the parallel pre-heaters both thick wires and one of the thin ones need to be joined together (one end of the balast is a convenient point to do it) and the other thin wire needs to be connected to earth. the earth wire to the front end of the engine, that used to go to the front pre-heater, needs to be taken off.

It is not unknown for the newer pre-heaters to be fitted but the thin bulb wires get left in the old positions, this will stop the bulb from lighting.
Regards rog8811

Click to expand...

I found this out the other day when I started to rewire my series 3, although my cold start bulb wasn't wired in at all and one of the previous owners had also removed the balast resistor completely.
One question though is you have the glow plug feed going to number 2 plug I have the feed on mine going to number 1 plug will this make any differences to the resultant voltages at each plug or does it not really mater??

you have the glow plug feed going to number 2 plug I have the feed on mine going to number 1 plug will this make any differences to the resultant voltages at each plug

Click to expand...

The reason for it, I believe, is that if a wire comes loose from one of the pre-heaters more of the remaining ones are going to still work. see quick and dirty drg below.

Regards rog8811

rog8811 said:

The reason for it, I believe, is that if a wire comes loose from one of the pre-heaters more of the remaining ones are going to still work. see quick and dirty drg below.

Regards rog8811

Click to expand...

Cheers rog8811 that clears that up then will move feed to plug 2 the weekend

On my series 3 (with original ballast resistor and plugs), theyre controlled by a manual switch and my cold start light starts off completely out, then the light "warms up" and fully illuminates....

Not to worry though as I ripped out all the wiring and going to start from scratch

When I had a diesel SIII (have petrol now) I changed the glow coils for glow plugs, and when installed the cold start light worked for the first time! The coils were a charred and corroded mess I assume this is why no light; God knows how it ever started on those coils! Well worth the upgrade, pretty cheap and made starting much easier. New ballast resistor isn't much either.