An HJ60 parasitic draw story (1 Viewer)

[Uncharted]

Hi everyone,

Hoping for some advice. I have a RHD 1985 HJ60 that spends its winters in a garage about 15 mins away. This year, I went to start it up as I periodically do throughout the winter months and the thing was dead. I've had the cruiser for several years now and up until that moment it had started on first crank EVERY TIME. Checked the batteries and they were dead, put new ones in there and then came back to it a few days later and it was dead again. So I went on a hunt. After doing some Mud reading and Youtubing (zero electrical knowledge or background) I bought myself a multimeter and started pulling fuses. I believe I've identified the circuit that it's coming from - the one for the power locks. Of note, the power locks in my rig have been non-functional for about 3 years, I've suspected it was due to a bad driver's side switch but never really cared enough to look into it.

During my hunt I discovered that the aftermarket stereo that was installed by the previous owner is wired into that door lock circuit. I think that is why the circuit appears to be 30A instead of the factory 15A that it was originally? Pic attached.

I took out the driver's side door card and detached the driver's side power lock switch to see if the switch was stuck and continually engaging causing the drain. When I put the fuse back in, the draw was still there.

Before I go down the rabbit hole of taking the dash out to get to the stereo I thought perhaps I should fully investigate the power lock system first. This brings me to my question: What is my best next step to investigate the power lock system at this point? I'm a novice to the level that I don't have any concept of even where to begin looking for the relays to test them or whatever else could be the culprit in that circuit. TBH I don't even how to test relays if I found them. Would really appreciate any guidance. Thank you

 

[ATL Cruiser]

Just to confirm - when you pull that fuse (the one for the locks and aftermarket radio), the draw goes away completely?

It's probably that radio circuit. Have you disconnected on the radio lead coming off that fuse? Does the draw go away then?

Last question, how are you confirming draw vs no draw? Do you have an amp clamp or inline amp tester at the battery?

 

[Uncharted]

Just to confirm - when you pull that fuse (the one for the locks and aftermarket radio), the draw goes away completely?

It's probably that radio circuit. Have you disconnected on the radio lead coming off that fuse? Does the draw go away then?

Last question, how are you confirming draw vs no draw? Do you have an amp clamp or inline amp tester at the battery?

Yes, when I pull that fuse the draw goes down to 13mA which I imagine is baseline for the truck.

Good point on evaluating that lead coming off the fuse. I will put a different fuse in that slot instead of the one with the presumed radio lead and check it.

I confirmed the draw by putting the multimeter in line with the ground of the “second” 12v battery in the series and checking the amount of amp output.

 

[ATL Cruiser]

I confirmed the draw by putting the multimeter in line with the ground of the “second” 12v battery in the series and checking the amount of amp output.

That is what I figured. That is a great way to find small draws. However, do not start the truck with that setup. It will melt your multimeter from the massive current dump. Use an amp clamp to find larger draws. I know from experience when I was young and more stupid.

Looking forward to hearing the results upon replacing the franken-fuse.

 

[Uncharted]

Update: as ATL Cruiser suspected, it appears that the issue is coming from the stereo. I removed the "Frankenfuse" and popped a regular old 15A breaker in the fuse box and tested it, no parasitic draw. I then started to follow the wiring (yellow) from the frankenfuse to see where it leads. It joined up with a red and black wire and I followed those to a metal box that is behind the glove box (see pics, the yellow wire appears to have been soldered to a red one just before the connection point). Is this the transformer they used to step down the voltage?

I found the installation instructions for this stereo and it appears that the yellow wire is hot to the battery, the red is for the ignition, and black is ground. I didn't follow those red and black wires in my underneath carpet pic, not exactly sure the path they take.

Also not sure how to think about this next from a troubleshooting standpoint. The draw occurs when the cruiser is off yet the stereo also remains off when the circuit is connected. When I turn the car on, the stereo would turn right on. I imagine that means the aspect of the wiring related to the ignition is OK and the draw is somewhere along the route of the yellow wire? How can I stepwise test that theory? Thanks.

 

[ATL Cruiser]

Great find and great questions.

I'm glad that wiring was fused. Good gracious, a raw, hot wire sitting right under the carpet in a wear zone. Over the years, those would have worn right through and eventually shorted out against the body. Gross.
Regarding the boxes behind the dash. That is where the normal 24V/12V stepdown transformer resides. My HZJ77 only has one transformer on the top left. It looks like yours has two. Additionally, yours appear to be aftermarket units. Do you have a good wiring diagram for this truck? The transformer should be shown in there somewhere. You can find PDF's in the RESOURCES section across the top toolbar.


The first thing I would figure out - why are there two transformers? (unless that is normal in a 60?)

The next piece I would test is which radio lead is pulling the draw. The 77 transformer has an "always hot" lead and an "ignition on" lead (i.e. 12V only with key on). Figure out which one of these two is pulling from the radio.

Essentially, I think either your transformers are shorting internally or your radio is shorting internally.

 

[jblueridge]

I had a similar problem when I installed a 12V radio.
The Pyle 24-12V converter drew too much power just to run the radio’s clock and memory when the ignition was off.

 

[Uncharted]

Sounds like I need to target the transformer. Will report back soon. Thanks for your help guys.

 

[jblueridge]

You can see what I did via link beliw.

12V radio fix