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View Full Version : Chasing Electrical gremlins (AKA 12v 101)- FJ60 (long)


CardinalFJ60
01-13-2012, 05:54 PM
I'm rolling up the sleeves with multimeter in hand and gonna try like heck to figure out what's going on this Sunday. A fellow 60 owner who's got some 12V electrical skills (thanks Boland!), and I are going to put this one to rest. it'll be great to have 2 fj60s side by side.

I've always struggled with a slightly low voltage on the 60, that would come and go, sometimes with rain/wetness. But definitely not right. in the past (years ago, now) when starting the vehicle the volts would read a little low on the dash, then, I'd hear a distinctive "click" (think relay click) on the PS of engine/kickpanel?? and the volts would jump to normal. This is waaaaay before dual batteries, headlight harness, ARB compr. etc.

I started to really look closely before the Outlaws run this year (http://www.risingsun4x4club.org/forum2/showthread.php?t=16456&page=3&highlight=wimpy)

Fast forward...

Lately, when I stop the truck, I can watch my dual battery meter drop from running voltage (13.8+) down to like 12.4 and 12.6 within 10 seconds. a day later, and the starting battery (BRAND new red top) is down to 12.2. And that's with nothing "on".

I checked, cleaned and reattached the ground at the rear lid near the wiper as my cargo light is a little funky.

Other interesting facts...
New alternator (stock)
new red top
New yellow up

I disconnected both batteries and borrowed a CTEK US800 charger, put that on the red top and after 4 days, it never when to "maint' mode. :confused:

Here are added aux devices, I think I'll start with these...any tips on testing?
- dual battery V-sensing relay
- foglights
- ARB compressor
- Radio amplifier/FM Radio
- ARB bumper harness (blinkers....hey Nakman, we set those up "disco" style and my blinker indicator glows slightly with lights on. you told me about that, but now I forget why)
- winch (older M10000)
- ARB aux headlight harness
- CB

How do I check for "bad grounds" or bad relays?.

I understand there are many "switched ground" circuits...help me understand this. :o

any other tips, grounds to be sure to check, you're experiences etc...would be great. I'm 'this close' to losing sleep over this problem

thanks everyone! And RZeppa...thanks for the offer for the "12V 101" class...I'm still game.

CardinalFJ60
01-16-2012, 08:21 AM
Battery voltage this morning - :D

Starting: 12.73
Aux: 12.82

Yesterday, with multi-meter in hand we went through every circuit to find the parasitic drain. It was minor enough where it wouldn't kill the battery overnight or anyting that dramatic, but after just a couple days sitting, my brand new red top was only at 12.4-12.5ish.

Sean's Fj60 at rest was drawing about .01amps (I'm pretty about the decimal placement :o ) Mine... .08 - almost ten times the draw. We isolated the drain to the Dome circuit. Wanna know what else is on that?? Carb Cooling fan relay. :thumb: BTW...the Carb cooling fan relay is on the PS kick panel.

Here's the weird part, it took a little while to figure out. As we were checking the circuits at the fuses, we found pulling the dome fuse eliminated the draw. And upon replacing the fuse, still no draw. When I keyed the ignition to Acces. then On, then back to Off...the draw was back at .08. Repeat...pull the fuse, no draw, turn it on...constant draw. went through everything and that Cooling fan relay seems to be the culprit.

I now know how to check for current, voltage and isolate circuits. :thumb: :hill:

:risingsun