1987 HJ61 Pre-heating system not working

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ChangingMan

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Hello everyone. I guess I’m really looking for Europeans, Kiwis and Canadians for help, although any Aussies living in Tassie or even colder parts of Victoria might be able to contribute.

My problem began with finding out that the pre-heating timer on my ‘87 HJ61 had rusted out. I guess the truck sat in water sometime in it’s past. I have replaced the timer but the system still won’t work. What I can’t work out is how many relays there are to supply the actual pre-heating element with power. I’m thinking there should be two - one for the pre-heat and another for the post-heat. Or is it just one relay + a resistor to reduce the power when in post-heat mode?

Any help greatly appreciated as I’m in about -5 centigrade now and the truck doesn’t like starting up in the morning! Thanks
 
sved

sved

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Feb 24, 2012
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As you can see in this picture your
after glow relay is missing.
20211128 205238

The pre glow is not working because your heater timer is stuffed.
Still the after glow main current which is controlled by the afterglow relay is hardwired directly to the glowscreen, if it is true what you say that the wire is still connected to the glowscreen.
I do not believe that, because your battery 's would be drained very quickly.
 
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ChangingMan

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Feb 22, 2021
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Italy
As you can see in this picture your
after glow relay is missing.
View attachment 2850415
The pre glow is not working because your heater timer is stuffed.
Still the after glow main current which is controlled by the afterglow relay is hardwired directly to the glowscreen, if it is true what you say that the wire is still connected to the glowscreen.
I do not believe that, because your battery 's would be drained very quickly.
I think the glow system is not working because the pre-glow relay isn’t working and remains open. If that relay remains open then I guess the batteries will not drain?
 
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ChangingMan

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Feb 22, 2021
Messages
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Italy
I think the glow system is not working because the pre-glow relay isn’t working and remains open. If that relay remains open then I guess the batteries will not drain?
I haven’t checked the coolant temperature sensor yet, so it’s possible that it also doesn’t work

CF118CC0 A525 4740 AC07 A499FBBAFBB1
 
sved

sved

Joined
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Messages
735
Location
Sweden
Yes if your pre glow is not activated when turning the key to glow ,you will not have any glow at all.
Are your fusible links ok ?
The ones close to the 24v battery post. Look at the diagram i posted.
Do you have 24V at the relay ?
 
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ChangingMan

Joined
Feb 22, 2021
Messages
38
Location
Italy
Yes if your pre glow is not activated when turning the key to glow ,you will not have any glow at all.
Are your fusible links ok ?
The ones close to the 24v battery post. Look at the diagram i posted.
Do you have 24V at the relay ?
I will check tomorrow ✅
 

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