L300 Parasitic Voltage Drain ?!!!

deskinthewoods · Post by **deskinthewoods** » Tue Feb 18, 2020 10:44 am

A week ago I came out to start the van, after a -21C night and the battery was dead. I thought I must have not closed the door properly; sometimes the seat belt gets caught in the door...
The battery was frozen solid. I brought it in and thawed it out, tried to charge it but it was a goner.

Bought a new one at Canadian Tire, installed it and the van fired right up no problem. Drove it every day that week.

Saturday, came out, and same exact thing. Frozen solid. Thawed it out. Wouldn't hold a charge. Took it back and got a new one under warranty (don't mention that you froze the battery

). Installed it, the van fires up beautifully, drove it into the garage, and checked to see if there was a parasitic drain.

Yup, with the key out and all doors closed and lights off, 3 amp draw. Pulled all the fuses one by one and no drop in the draw. Disconnected the battery for the night.

Spent the evening on the google machine. I learned that sometimes the diode in the alternator goes, sometimes a relay can get stuck, a couple things to check in the morning...

This morning I go out to the garage and...NO PARASITIC DRAW!!! Nothing!

So, immaculate corrections aside, does anyone have any ideas as to what happened or is happening? I've left the battery hooked up and the van is in a heated garage so if it happens again overnight I won't freeze the battery...

deskinthewoods · Post by **deskinthewoods** » Wed Feb 19, 2020 7:55 am

I still have the drain. The fuse in my multimeter blew.

deskinthewoods · Post by **deskinthewoods** » Wed Feb 19, 2020 9:18 am

Getting closer. The drain stopped when I pulled the fusible link for the lights. However pulling the fuses in the fuse box did not stop the drain.

So, would that indicate a ground fault between the fusible link and the fuse box? I’m thinking so.

sck_nogas · Post by **sck_nogas** » Wed Feb 19, 2020 12:25 pm

I had a similar issue with a parasitic drain. Turned out to be the diode of my alternator. I found it by putting my battery on a trickle charger and let the car sit overnight and cool. Used a FLIR thermal camera to "look" for heat and the ONLY thing that was above 65-70F was the alternator at 105-110F.

More here...
https://delicaforum.com/index.php?threa ... #post-3982

deskinthewoods · Post by **deskinthewoods** » Wed Feb 19, 2020 3:00 pm

I disconnected the alternator at the battery and still had the drain.

deskinthewoods · Post by **deskinthewoods** » Thu Feb 20, 2020 10:52 am

Thanks for that link, sck_nogas. I considered the battery isolation switch but decided to just isolate the offending circuit: Lights.

I installed a simple toggle switch in the dash

: switch.jpg (30.45 KiB) Viewed 8556 times

and wired it in just behind the fusible link junction box (down stream from the fusible link). I used spade connectors so it will be easy to reverse if I ever track down the drain.

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I used to wish I had big muscled arms but not so much now...

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So, here's a new twist. One of the other little jobs on the list was to fix the fuel filter indicator/glow plug indicator that stopped working a few weeks ago.
With the new switch turned off the fuel filter lamp works (as well as the battery indicator which I hadn't even noticed wasn't working).

: switch off.jpg (18.96 KiB) Viewed 8556 times

With the switch turned on neither works.

: switch on.jpg (22.02 KiB) Viewed 8556 times

Any ideas what this could mean? Does it indicate where this parasitic drain is?

deskinthewoods · Post by **deskinthewoods** » Sat Feb 22, 2020 4:40 pm

The next job on my list was to replace the radiator hoses and thermostat. As I was removing the thermostat housing bolts I dropped the ratchet and it hung up in the wire loom below...and the loom started to smoke. On closer inspection the smoke was coming from the connection at the alternator where the protective rubber boot had split and the wires were grounding to the alternator body...parasitic voltage drain found!!!

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I cleaned up the wires and the broken boot (I couldn't get a new one locally today) and gooped it all up with dielectric grease and zip-tied it back together. I reoriented the wires a bit so they weren't touching anything.

: parasitic drain3.jpg (25.34 KiB) Viewed 8530 times

So, now I have a toggle switch on my dash that does nothing...maybe I'll use it for a manual glow plug switch....another day...

And all my dashboard lights are working properly again! I need to study the wiring diagram. None of this seems logical in the slightest...