How to identify the glow system

[Full_Throttle]

I apologize if this is listed somewhere, but I have been searching and can't seem to find the info. I am searching for.

How do I tell which glow plug system my BJ73 has(1985 BJ73 RHD from Aussie)? I have read a few threads that mention a super glow system that uses 6V glow plugs, and a "timed" system that uses a different voltage. I thought I saw that the super glow system was behind the glove box so I looked. I didn't find what I was expecting.....I did find a small black box mounted in-between the glove box and the radio with the part number 077300-0660 but that didn't seem to correlate with anything I was finding on this forum. A google search shows it as a Diesel glow relay. I would like to replace my glow plugs, but until I know which system I have it is hard to test to see if everything is working as it should.

I am considering just bypassing everything and install the Wilson switch with Bosh 0250202058 glow plugs.

 

[roscoFJ73]

Is the part number correct, I cant find it in the parts diagrams. These are the 2 numbers for the glow timer
28521-57060 (11/1984 - 09/1985)
28521-57061 (10/1985 - 07/1986)
It is where you were looking, from memory its bit lower down.


This is the part number for your glow plugs is 19850-68050. They are 12v-6v

I think that little black box may be the A/C amplifier, they often get confused with glow controllers. The part number could be a Denso part number.
I don't think the Australian models had the super glow

 

[Full_Throttle]

Is the part number correct, I cant find it in the parts diagrams. These are the 2 number for glow timer
28521-57060 (11/1984 - 09/1985)
28521-57061 (10/1985 - 07/1986)
They are where you were looking, from memory its bit lower down.


This is the part number for your glow plugs is 19850-68050. They are 12v-6v

I think that little black box may be the A/C amplifier, they often get confused with glow controllers. The part number could be a Denso part number

Well, I don't truly know what it is, but I agree it isn't what I expected.

Is it in a different location? There was nothing behind my glove box at all that resembled electronics. Especially what is shown in the pictures I found on the forum.

 

[roscoFJ73]

AFAIK, all 7* series have the glow controller in the same place and the parts diagram shows it behind the glove box.
Maybe someone has tampered with it .
I think I have an AC amplifier in the shed with a number like that and there are a couple on ebay.

What is actually wrong with your glow system?

 

[Full_Throttle]

I decided to go and look again. Here is a picture behind my glove box.

behind the glove box

• Full_Throttle
• Oct 25, 2018

But when I stuck my head in there and looked UP, I found what I was looking for.

Glow timer

• Full_Throttle
• Oct 25, 2018

So this should help me in determining which system I have.

 

[Full_Throttle]

What is actually wrong with your glow system?

Maybe nothing....but until I know exactly which system I have I can't take measurements to confirm that it is working as it should.

It is not very cold here (yet) and in the mornings this vehicle is hard to start. Temperature is maybe 45-50 degrees F.

I need to do a compression test so I know where I stand with this engine. IF I am going to be pulling the plugs anyway, why not go ahead and replace them. IF I am going to replace them, do I go with the Wilson switch mod?.......

Anyway, that has been my thought process. I am leaning towards 10.5V plugs and the Wilson switch mod. I like the control factor.

 

[coldtaco]

if your factory system is still working I would keep it. Works good last long time or at least till now? Safety factor especially if someone else had to drive it.

 

[roscoFJ73]

Maybe nothing....but until I know exactly which system I have I can't take measurements to confirm that it is working as it should.

That's what you need the FSM for. They normally detail the electrical specs for various markets.
There are free 3B manuals if you look around

When those pre timers are not working right they often have burnt out parts on the circuitry you can see when you take the cover off.

IF I am going to be pulling the plugs anyway, why not go ahead and replace them. IF I am going to replace them, do I go with the Wilson switch mod?.......

Im with Coldtaco. The factory system works great. If it dies , I will probably use an aftermarket timer that is adjustable.

 

[Full_Throttle]

I will be going the Wilson Switch route. I found a great deal on the new glow plugs, and I really like the idea of having full control over my system. I live by the KISS method.....nothing simpler than a switch to a relay

Thanks for the help guys!

 

[perrobravo]

Your system (the timer at least) looks like that on my 24V BJ74. My caveman-level understanding is that timer uses a signal from a water temperature sensor to decide to give power and how much to the glow system. If the water temperature is below a given level, it comes on while the key is in the on position, and a light on the dash indicates the system is working. If you unplug the sensor, the system will come on whenever the key is on.

Following the test instructions in the FSM are pretty easy and even with my very limited knowledge, I came to appreciate the system's simplicity and share the same sentiment as @coldtaco and @roscoFJ73 . I also discovered my truck needs that system to work at far higher temperatures than I've seen others reporting here. Perhaps yours is the same in that regard.


Here's some additional, potentially useless anecdotes and the story of how mine behaves. The short version of this is that my truck needs the system to work even at higher temperatures than would seem to warrant it. Could be yours is the same.

-----

I recently had both relatively new batteries go bad and so (without much real evidence) I started to blame the big amp draw of the glow system which was coming on every time I turned the key on in my BJ74...regardless of the ambient temperatures (I'm in San Diego, so >75F is common). Yes, I could just twist the key to start the engine, but sometimes I just want to roll up the windows and the glow system would be drawing a ton of current.

This seemed odd, so I tested the temperature sensor the pre-heat timer uses to decide whether to do its thing. It seemed to work, so, I decided to simply disconnect the harness going into the pre-heat timer, figuring I don't have plans to be in actual cold weather any time soon, don't want my new batteries to suffer, and didn't feel further diagnosing a system I didn't think I'd need.

Fast forward a week to a cool (maybe 50F) morning at least 60 miles from pavement on my way to the Southwest 70 series event. Normally the truck starts instantly with barely a tap on the ignition, but when I went to start the truck that day, it just cranked. Not a good feeling so far from civilization.

So, I plugged the pre-heat timer back in and the dash light indicating the glow system is on didn't do anything and there wasn't the usual significant drop in voltage (as I've typically seen on the dash gauge). Hmmmm. I then unplugged the temperature sensor to force the system into action and the truck started right up after a few seconds of pre-heat love.

My conclusion: For whatever reason, my truck needs the glow system to work, even at relatively higher temperatures than others have said it should. No idea why that would be. Also, I must have previously had a bad connection to the sensor which was causing the system to run all the time. Then after futzing with it in the last week or so, it came back to life, operating as it should...which I then had to disconnect to get the system working even at ~50F.

HTH