HDJ81 1HD-T Won’t Crank, What am I Missing? (1 Viewer)

[kw90surf]

Good day,

My recently acquired HDJ81 recently developed a no-crank issue. I’ve only started the thing maybe 10 times, but there was no real warning, just one day it wouldn’t start (previous owner claims to not know anything about it).

Weirdly, at the same time (as far as I can tell), the headlights, horn, hazards and dome light all stopped working as well. All of these things (except starting) are powered from the under-hood fuse panel. The terminal in that panel is getting 12V and two of the pins on the headlight relay are also getting 12V (as they’re supposed to) but the relay won’t engage and I tried swapping relays to no avail. Pulled all the fuses and they look good.

On to the STARTING issue:

When the key is turned, several relays click and clunk, the dash lights go out, but nothing happens.

- tried swapping batteries, boosting, etc. Batteries do not appear to be the issue. Replaced and cleaned up the terminals as well.

- 12/24 switching solenoid works (clunks), and sends 25.6V to the bottom post of the starter when the key is turned. Good.

- replaced the contacts on the starter (one was toast), filed the plunger and bench tested it. All tests checked out okay and works as it should. Spins when 12V is applied to trigger wire.

- starter relay engages when key is turned, but I pulled it off and bench tested it and tests all checked out.

- fusible link in starting circuit jumped with 10ga wire, made no difference.

When the starter is installed in the truck, turning the key engages the 12/24v solenoid, sends 24+V to the bottom (battery) post of the starter, but there’s no voltage at the top (starter motor) post which is telling me the plunger isn’t connecting the contacts. But, the starter relay is engaging, which would make me think that the trigger wire would be getting 12V (which I can’t currently verify as I don’t have a helper, but would explain the issue).

This truck is a manual, so no NSS.

I’m getting real puzzled here. Any ideas what would prevent the trigger wire coming from the starter relay to not deliver 12V? Is the fuse box issue related?

 

[AirheadNut]

I had the exact same issue with an HDJ81 once, it turned out to be a short somewhere in the wiring between the + Battery and the B terminal of the starter relay. I ended up running a new fused wire. There could also be an issue with the wiring between the MG terminal of the starter relay and Terminal 50 on the starter, mine had a lot of oil and gunk built up on the plug that can't have helped things.

HDJ81 24v Starting System Issues

After a week and a half of sitting in a garage my HDJ81 is refusing to crank. Everything seems to work normally until I turn the key to the "start" position, when a bunch of relays can be heard clicking but the starter doesn't even try to crank. So far I have tested the following: -Starter...

forum.ih8mud.com

 

[Squash]

Try the fused wire trick . Mine bypasses everything from the battery to the starter relay.
Also added a fused momentary switch which offers 12v starting or just to bump the engine.

 

[kw90surf]

Well after hours and hours of troubleshooting I finally figured this out.

I narrowed the starting issue down to the 12V trigger on the starter. If I had someone turn the key to “start”, thereby putting the batteries in series and sending 24V to the bottom post on the starter, and I applied 12V with a jumper wire directly to the bottom terminal (MG?) on the grey plug that comes from the starter relay (the one that runs directly down to the trigger on the starter), the truck would reliably start.

12V from the battery comes down to the other terminal on the grey plug (terminal B I believe) and when the starter relay closes “B” and “MG” are made continuous and then the 12V from the battery goes down to the starter and triggers it to spin. So, I was getting 12V at the supply terminal B, but when I had someone turn the key and measured the voltage down at the starter it was only 1-2V. But when I applied 12V to the MG terminal it would trigger the starter, which ruled out that run of wiring as being the issue.

So this narrowed it down to either the 12V supply (shorted or bad connection such that it would read 12V but when a load was applied it would short) or the starter relay. I had already bench tested the starter relay but I pulled it apart to check the contacts. They were fine. I checked the voltage going through it and there was no abnormal drop so I ruled it out.

So I finally started to trace the 12V supply wiring from the battery to the starter relay. Lo and behold, I found the following:

This plug was located under the washer fluid reservoir. If I had to guess, a leak and/or 30 years of overfilling/spilling washer fluid on this plug finally nuked it. The white wire is the 12V supply for the trigger wire for the starter. It must have been just connected enough to show 12V when checked but once a load was applied it couldn’t support it. I re-did this plug and not only does it now start at the first bump of the key, but all of the other stuff (headlights, dome light, horn, hazards, radio, clock) now works as well. I had suspected (and hoped) they were related.

Anyways, I hope if anyone has these symptoms in the future they find this thread to be of use to them because not being able to figure this out was starting to drive me nuts.

Thanks to @AirheadNut and @Squash for chiming in, and further reinforcing that the issue was in the trigger supply for the starter.

 

[roscoFJ73]

Good work and shame on Toyota for putting an important component under there.

 

[AirheadNut]

That's fantastic that you were able to find the issue! As luck would have it, just today I was looking at my brother's HDJ81 (the one I used to have) and when I saw your reply here a lightbulb went off. He has been having the same sorts of issues lately: clock, stereo and dome lights were all on the fritz. I went ahead and tore out the washer fluid tank and sure enough that same plug was badly corroded, with several wires completely disconnected. It looks almost exactly like the photos you posted. Hopefully going to tear into it this week. Where did you get your repair terminals from?

 

[Squash]

Brilliant!

 

[kw90surf]

That's fantastic that you were able to find the issue! As luck would have it, just today I was looking at my brother's HDJ81 (the one I used to have) and when I saw your reply here a lightbulb went off. He has been having the same sorts of issues lately: clock, stereo and dome lights were all on the fritz. I went ahead and tore out the washer fluid tank and sure enough that same plug was badly corroded, with several wires completely disconnected. It looks almost exactly like the photos you posted. Hopefully going to tear into it this week. Where did you get your repair terminals from?

Glad to hear that was helpful. To be clear, I haven't rebuilt the connector yet, I just went super ghetto and cut the male plug off, stripped and crimped on some trimmed-down spade connectors, and then zip-tied them once attached so they wouldn't fall out. Not a permanent solution, but the truck has been sitting dead in my parent's driveway for months, suppertime was closing in and I was leaving to go to sea for a month the next day and wanted my father to be able to move it if he needed. I'll be sourcing terminals and attempting a rebuild on the plug when I get home in a month. If that doesn't pan out, my cousin might be able to score some waterproof electrical connectors from work. I'll post what I end up doing on this thread.

 

[SnowVersion]

I'm the owner of the HDJ81 @AirheadNut mentioned earlier. Here's a thorough description of the electrical issue as it has evolved over the years.

1. Vehicle would not crank. Dome lights, clock, radio, etc still operational. Cranking is the only issue. As @AirheadNut mentioned, running a new wire between the + Battery and the B terminal of the starter relay solved the no-crank issue.
2. A year or two later, the hazard lights stopped working. Never bothered looking into this issue.
3. Fast forward a couple more years to the present and the clock, dome light, map light, radio all start working intermittently. It's worth noting that the illuminated ring around the key hole and the seat belt/door open warning lights in the gauge cluster continued to work.

In an attempt to resolve the intermittent dome light et. al. issue, @AirheadNut and I checked the 10-pin plug that @kw90surf highlighted as his problem. Tons of corrosion there. 4 of the 9 wires broke in half before we could even get the plug undone.

The old wires

New plug wired in

After repairing the plug, there were a couple changes:
- Hazard lights now work
- Illuminated ring around the key is now broken
- Seat belt and door indicators in the gauge cluster are now broken

No change to the
- Dome light
- Map light
- Radio

I rechecked fuses, but they were all good. Time for further diagnosis!

 

[SnowVersion]

Rookie mistake... I replaced the male side of the plug, but neglected to examine the female side of the plug. Turns out, the corrosion had spread and at least one wire is now broken. Hopefully replacing the other side of the plug will take care of the misc. electrical issues.

 

[kw90surf]

Rookie mistake... I replaced the male side of the plug, but neglected to examine the female side of the plug. Turns out, the corrosion had spread and at least one wire is now broken. Hopefully replacing the other side of the plug will take care of the misc. electrical issues.View attachment 2667864

Glad to see you're getting it sorted! Did you get your hands on another pigtail from another truck?

 

[SnowVersion]

Glad to see you're getting it sorted! Did you get your hands on another pigtail from another truck?

The same guy I got the male plug from also has the female side available. But I ended up taking off on a 10 day road trip this morning. I guess the dome lights will have to wait!

 

[kw90surf]

The same guy I got the male plug from also has the female side available. But I ended up taking off on a 10 day road trip this morning. I guess the dome lights will have to wait!

Envious, enjoy!