Internal wiring of BJ40/BJ42/HJ42 glow relay (Manual glow)

[lostmarbles]

.....
This page from the EPC has added to my confusion. I was trying to see which plugs a 12V manual-glow H engine was supposed to run. .... And low and behold I come with those horrid words "Main" and "SUB" again.

What does anyone make of this?

....

Well at least I can answer that question I had in post #54 myself now.

Apparently the "SUB part number" in that glowplug printout is not a glowplug at all but just a "subsidiary part" associated with the glowplug:



So - That's a different slant on the word "subsidiary" compared to what I had imagined.

(I've gained a bit on how to interpret EPC data! )

 

[amaurer]

Incidentally, without disconnecting my starter control circuit, I found it is hard to tell (from my controller) whether or not my plugs were still getting juice via my glow controller. That's because the controller began to dim as soon as I turned the key away from the glow position, and my engine starts so easily that the key doesn't stay in "start" long enough to see the controller glow brightly again.

So the controller DOES glow in the Start position when you did your test, right?

x2 we need someone with a 24V manual glow truck to do the same test and tell us if the controller glows in both glow and start.

 

[lostmarbles]

So the controller DOES glow in the Start position when you did your test, right?

Yes. (I got the same result that you got with yours Drew.)

...x2 we need someone with a 24V manual glow truck to do the same test and tell us if the controller glows in both glow and start.

Yes.


PS. I think we can now be pretty confident we have our 12V start/glow situation figured out. (But I just want to perhaps modify that 12V diagram a tad more with respect to the fusible link because I'm so pedantic about trying to get absolutely EVERYTHING there right and in agreement with my current knowledge/understanding. )

 

[KOOTENAY KRUZER]

If I remember come spring when the snow is gone I will try it with my BJ40 but right now the snow is wet and soggy and over the running boards. Since I use a "center tap" 12V system for 12V accessories and the truck has been basically parked for a couple of years the low (ground side) battery is toast and has to be jumped. My friend has had his driveway plowed and the excess snow is piled where I need to drive to get the BJ42 up there and SOA or not I don't think it can do it.

 

[lostmarbles]

If I remember come spring when the snow is gone I will try it with my BJ40 but right now the snow is wet and soggy and over the running boards. Since I use a "center tap" 12V system for 12V accessories and the truck has been basically parked for a couple of years the low (ground side) battery is toast and has to be jumped. My friend has had his driveway plowed and the excess snow is piled where I need to drive to get the BJ42 up there and SOA or not I don't think it can do it.

Thanks Wayne.

When the snow melts it is quite an easy test to do by unplugging that connector near your starter motor. (I found I couldn't unplug any connector at my starter relay because that relay was tucked tightly behind my wiring loom to make access difficult.)

 

[AJAEbj42]

Manual Glow not turning off

Hi there,

This is a great thread. Thank you very much for all of your efforts here as it came in handy this morning when my 1981 CDN BJ42 manual glow would not turn off!

My truck also has the separate glow switch in the dash as well as the ignition 'glow' switch (turn the key backwards from OFF).

Here is the 24V Glow plug relay:


Here is a pic of the 'welded' relay tabs; this was the culprit!


Incidentally, when I press either the glow switch on the dash or use the key ignition 'glow' setting, the same relay coil and only one is energized (the one with the goop on it that I need to clean!). The 'green glow' is the relay points arcing. Cool effect, but of course not desirable! Blasted 24V welds anything almost instantly if it arcs. I had a similar problem with my turn signal relay


When I turn the key to START, the other relay coil is energized, but not the first one. When I let go of START and the key is in the ON position, (i.e. when the engine starts), the second coil is no longer energized. When the engine is running (on a cold CDN day!), I can press the dash switch, which will give me some extra glow; again, only the first coil (the one with goop) is energized.

And yes, my glow screen will 'glow' with the engine running when I press the dash switch.

Anything else, you'd like me to test, while I clean the points today?

 

[lostmarbles]

Thanks for posting this AJAEbj42.

I've been re-reading the entire thread to try to get back up to speed on where we got to (while I should really be spraypainting parts of my cruiser on this lovely fine saturday morning).

.... when I press either the glow switch on the dash or use the key ignition 'glow' setting, the same relay coil and only one is energized (the one with the goop on it that I need to clean!).


When I turn the key to START, the other relay coil is energized, but not the first one.

When I let go of START and the key is in the ON position, (i.e. when the engine starts), the second coil is no longer energized.

When the engine is running (on a cold CDN day!), I can press the dash switch, which will give me some extra glow; again, only the first coil (the one with goop) is energized.

And yes, my glow screen will 'glow' with the engine running when I press the dash switch.

Anything else, you'd like me to test, while I clean the points today?

So that "other" set of contacts closes ONLY when your key is turned to "start".

As far as I can make out, the main thing I wanted to know was if this set of contacts supplies the "S terminal".

If it does, it will be bypassing your "glow controller" (the coil of wire in your dash that glows) which means:

• the glow controller won't glow when your key is in "start" (despite the fact that it glows every other time your glowplugs are "glowing"), and
• your glowplugs will be getting higher voltage while cranking (than they would if their current was always routed through the glow controller - like mine is)

The simplest way to check this is to unplug your starter solenoid connector and turn your key to start and see if your glow controller glows.

But don't do it for more than 10 seconds because your glowplugs should be glowing well-enough by then and you should never have to crank for more than a few seconds at most anyway. After all, we don't want to overheat your glowplugs. (And 10 seconds should be long enough to get your controller to glow if the current were to be flowing through it.)

So it would be great if you could do this little test. (Post #60 shows my starter solenoid connector undone.)

Thanks heaps

 

[AJAEbj42]

When I turn the key to 'Start', there is 24V going to both the G and S terminals (the two outside terminals). When I hit my Glow switch on either the dash or the ignition column (key), there is 24V going through both terminals. The two coils are actually joined together.

My truck starts within 1/2 second of turning the key after a good 'glow' (manual says to glow for 20 seconds). So, my thinking, powering the 'S' terminal (when the key is turned to START), really isn't necessary.

I think this is where a Simple 'Wilson Switch' may be used in place of this relay, which incidentally was $292(CDN) from the Toyota dealer should I ever choose to replace it!

 

[lostmarbles]

When I turn the key to 'Start', there is 24V going to both the G and S terminals (the two outside terminals). When I hit my Glow switch on either the dash or the ignition column (key), there is 24V going through both terminals. The two coils are actually joined together......

Thanks AJAEbj42. But are you sure the voltage at your "S terminal" isn't a bit less when glowing (rather than cranking)?

I suspect your glow/start wiring is like this: (Simplified version)



In which case I'd expect you to get 24V at both "G" and "S" with your key in the "start/cranking position" but I'd expect you to find a lesser voltage (around 20.5V) at "S" whenever you attempt to glow without cranking (using either your key or momentary switch). (ASSUMING YOU ARE DOING YOUR TESTS WITH NO WIRING DISCONNECTED FROM THE GLOW RELAY.)

But at least finding 24V at both "G" and "S" does prove that your "S terminal" must be being supplied with 24V from within the relay enclosure. (Unlike our 12V BJ4#s where the S terminal is a dummy.)


By the way -Starting with just 1/2 second of cranking is a sign of a good engine.

 

[AJAEbj42]

Hi Tom,

The voltage could have been lower than 24, sorry I quote everything as either 12 or 24 volts! My buddies always joke with me about my rounding everything!

Yes, your wiring diagram looks correct.

351,000 km on the engine and doesn't smoke, or leak. I am quite fortunate that the previous 2 owners took good care of her over the first 25 years of her life. I change my oil and filter 3X per year (regardless of how much I drive her, which is only about 10,000 km as this is my weekend camping/cruising truck.

 

[lostmarbles]

.... I change my oil and filter 3X per year (regardless of how much I drive her, which is only about 10,000 km as this is my weekend camping/cruising truck.

Wow! .................And I thought I pampered mine with one change per year!

Edit: - I've just replaced that last wiring diagram in post # 69 with a modified version which shows the ignition switch in the same form as per the 12V diagram and includes the momentary switch (that was missing).

 

[NoeyR]

Gents:
I'm having a short circuit with my 24 volt, left hand drive '81 BJ42. So far what I've confirmed is that the BR (Black/Red Stripe) wire coming from the left side (driver's side) battery positive connection is being short to ground. Looking at the attached diagrams (circuit highlighted in yellow, zoomed out and in), it looks like the BR wire feeds the starter relay and the glow plug relay. Without removing and testing the relays yet, I'm just wondering what your thoughts are so far on this. Can the relay go bugger and short out or am I missing something?



[URL="http://img860.imageshack.us/img860/9362/electrical2.jpg"][/URL]

 

[NoeyR]

^ Oh forgot to mention that the BW and the B wire at the starter are not shorted too.

 

[lostmarbles]

Hi NoeyR

Just to clarify ....

You're saying you detect 0 ohms between that BR wire and the body/chassis when your key is off?

If that's the case I'd suspect the glow plug relay contacts have welded together (leaving your glow plugs on) or your ignition switch is faulty (energising your glow relay in the "off" position and leaving your glow plugs on once again).

Either way, your batteries would be discharging rapidly



PS. Another alternative is that the BR wire has chaffed through somewhere and is touching the bodywork.

 

[NoeyR]

Hi NoeyR

Just to clarify ....

You're saying you detect 0 ohms between that BR wire and the body/chassis when your key is off?

If that's the case I'd suspect the glow plug relay contacts have welded together (leaving your glow plugs on) or your ignition switch is faulty (energising your glow relay in the "off" position and leaving your glow plugs on once again).

Either way, your batteries would be discharging rapidly



PS. Another alternative is that the BR wire has chaffed through somewhere and is touching the bodywork.

Thanks for the reply lostmarbles. Yes that's correct, I'm detecting 0 ohms with no battery connected.

If let's say, there was no short, and I left the key in the igition, KOEO (key on engine off), with the batteries installed, can that lead to a constant energizing of the glow plug relay? I ask this because I think that's what I did prior to this occuring.

I need to diagnose this further to find the culprit.

I mentioned to a fellow cruiserhead the problem and he said that if the glow plug relay is gone, I clould put a switch in place of it. Any thoughts on that?

Keep you guys posted.

 

[WrenchMonkey]

Hey Rob if you ever want to fix this problem ask me to show you my truck I fixed it it glows quicker and it was fixed for $30 its been 2 years and not a single problem and replacement parts can now be had from lordco.

 

[lostmarbles]

Thanks for the reply lostmarbles. Yes that's correct, I'm detecting 0 ohms with no battery connected.

If let's say, there was no short, and I left the key in the igition, KOEO (key on engine off), with the batteries installed, can that lead to a constant energizing of the glow plug relay? I ask this because I think that's what I did prior to this occuring.

I need to diagnose this further to find the culprit.

I mentioned to a fellow cruiserhead the problem and he said that if the glow plug relay is gone, I clould put a switch in place of it. Any thoughts on that?

Keep you guys posted.

On a 1981 BJ42 I thought you normally needed to turn your key backwards (against spring pressure) to energise your glow plug relay? If so, leaving your key "on" (in the motor-run position) wouldn't energise it unless your ignition switch is faulty.

You could use a manual switch (momentary switch) in place of the glow relay but it would need to be rated for a high current. My 12V system's glow plugs draw a combined current of something like 40amps and I believe your 24V system draws around half that (20 amps).

However I believe most people who install a "momentary switch" (aka Wilson Switch) use a low-current version and keep their glow relay as well so that the relay still handles/switches the high glow plug current.

It boils down to personal preference. I try to keep my BJ close to OEM so I try to keep it wired close to OEM.

 

[NoeyR]

I managed to fix the problem today! After bumping around the starter and glow plug relays during their removal, I somehow managed to undo the short circuit. I initially suspected the glow plug relay so it has a removable cover which I took off. I found some evidence of rust in an area where a small wire is. It looks like the wire chaffed through it's insulation and touched a metal part (sorry no pic). There are two relay contacts where one was looking burnt. I applied electrical tape to the two small wires located close to a metal part, and sanded the burnt relay contacts clean. I installed two new Costco batteries (group 27 is physically the largest they have and fits the tray perfectly).

Lostmarbles, you're correct in that my ignition needs to turn backwards to energise the glow plugs. I also agree with you in keeping the electrical as close to OEM as possible. I'm not totally sure if my ignition switch is faulty at this point though.

The truck runs again! Thanks for all your help.

 

[lostmarbles]

I managed to fix the problem today! After bumping around the starter and glow plug relays during their removal, I somehow managed to undo the short circuit. I initially suspected the glow plug relay so it has a removable cover which I took off. I found some evidence of rust in an area where a small wire is. It looks like the wire chaffed through it's insulation and touched a metal part (sorry no pic). There are two relay contacts where one was looking burnt. I applied electrical tape to the two small wires located close to a metal part, and sanded the burnt relay contacts clean. I installed two new Costco batteries (group 27 is physically the largest they have and fits the tray perfectly).

Lostmarbles, you're correct in that my ignition needs to turn backwards to energise the glow plugs. I also agree with you in keeping the electrical as close to OEM as possible. I'm not totally sure if my ignition switch is faulty at this point though.

The truck runs again! Thanks for all your help.

Glad you got it fixed

 

[NoeyR]

For the 3rd time in 6 mths my glow plug relay shorted out causing the batteries to fry. I've taken the relay apart, cleaned it up, and applied dielectric grease to the contacts too. Does anyone know what the amperage requirement is for my glow plugs? Thinking of installing an inline fuse to the circuit off the high side battery for protection. Application is for a 1981 BJ42 24v 3B.