88 FJ62 Battery Drain

[SmallManBigMouth]

Ming,

I don't think it's a stuck contact. My rationale for opening up the rear door panel is to check all the crimp connections. If, when I pull that harness apart, everything's clean, I'll turn my attention to the master switch/driver's door harness.

Baldy,

I don't really understand what you mean. Are you saying that the way I metered might be affected by the switch on the negative side? Or are you saying that if I metered with the positive on the meter to the negative on the circuit it would make a difference?

 

[baldredhead]

Ming,

Baldy,

I don't really understand what you mean. Are you saying that the way I metered might be affected by the switch on the negative side? Or are you saying that if I metered with the positive on the meter to the negative on the circuit it would make a difference?

honestly i wasn't referring to your issues at all. sorry for the confusion. the way Wiley described the way to look for the shorted circuit has the meter checking drain by connecting the ammeter between the disconnected negative CLAMP and the still connected positive TERMINAL. i don't see where the electrical potential comes from, unless the battery in the multi-meter is providing the juice. just looking for a little clarity that's all.

i have no ideas regarding your windows, unless the tracks are sticky. sorry

 

[SmallManBigMouth]

No worries. Thanks for the clarification there. My goof really, you did include the quotes...

 

[Wile E Coyote]

Baldy,
Measuring from the neg terminal to the neg battery post will measure TOTAL battery current draw. Why disconnect the terminal? All that would do is test the tester? Ever read how much a battery can put out? It would fry any average multimeter (rated for 10 or so amps).
As far as the battery inside the multimeter, that would be used while checking ohms/resistance, not AMPS. Amperage is the amount of electrical current draw.
Disconnecting the neg terminal and measuring in the manner I described removes the direct-to-battery connection (which we know is good, and way high) and measures the draw produced by an electrical short/near short ANYWHERE else. NOT at the battery. A short is an abnormal connection back to ground outside the normal pathway. This is where the electrical potential COULD come from that you are questioning. If there's a short,(or a forgotten door open, or clock, or whatever) then the meter will measure it. This was the reply to the original post, not specific to SMBM's later question. SMBM's problem is concerning high RESISTANCE, measured in either ohms 9direct measure) or in the much lowered volt readings (indirect measure...remember what I said what happens to the volts when circuit draw raises way high due to high resistance?)

SmallManBigMouth,
The much lower volt measurement you got is exactly what we expected. You have evidence of high electrical resistance somewhere in that circuit.
What's voltage at the circuit breaker? Or as just posted, at the main lock switch? It's not in the motor's themselves.

When testing electrical circuits, always test from the source back, as it will isolate a problem with the least amount of unnecessary work. A bad battery will cause a bad reading at the end of the curcuit, but if you start at the end and work your way back, then only at the last check will you identify the problem.
Sounding even more fun, huh?

 

[SmallManBigMouth]

Wile E.,

Yeah...I know...drag. Anyhoo, it's measuring 11.7-11.9 at the Circuit Breaker. I'm on a trip at the moment, but when I get back in a week, I'll let you know how many crimps I take apart and solder, etc. And, if it fixes things.


Thanks again, buddy.

 

[Wile E Coyote]

Wile E.,

Yeah...I know...drag. Anyhoo, it's measuring 11.7-11.9 at the Circuit Breaker. I'm on a trip at the moment, but when I get back in a week, I'll let you know how many crimps I take apart and solder, etc. And, if it fixes things.


Thanks again, buddy.

You're welcome .
Be sure to check out that switch on the driver's door, before taking anything else apart. After another look at this, it seems that 's the most likely problem spot. Switches are notorious for raising resistance, right after corroded connections. Thank Ming for that reminder.

Good luck,
Mike

 

[SmallManBigMouth]

So, Wile E., and Ming,

It took a National Holiday for me to make time to finally pull everything apart and figure things out (sort of). Oh, the wife was busy gardening, so that helped as well!

I pulled the driver's door apart and got at the Master Switch, which is, as you can see, looks nice and clean from the front. (notice that nifty soldering job one of the previous owners did to repair the broken window lock switch)


Then, upon taking the doorlock switch apart, one of the culprits was revealed--dirty contacts. THANKS MING (was that subtle?)



I then used a pencil eraser to clean the crust/corrosion off and the voltage to the switch went from 7.8 to 11.96


While I had everything taken apart, I also soldered the crimp connections from the alarm sys. for good measure.

There's definitely more power to the locks now. However, the rear passenger lock is still a little sticky. I suspect that the harness from the door gasket there might be a bit crispy... So, I'll report what's up with that when I have a minute to work on it too.

I also decided to check out the condition of the window switches and their contacts as well. Let me be subtle again, PITA. Be very careful when opening the master switch for the windows. Each swtich has two rockers with contacts and three for the Auto Window switch. There are also little spring-loaded pins that want to jump out. I'm glad though that I decided to check it out; the contacts inside were also crusty. I cleaned them in the same manner as the door lock switch with a pencil eraser and the result is slightly faster moving windows.

A buddy of mine who fancies Audi's, BMW's, and VW's mentioned that in some models of aforementioned Euro cars, the same exact power window/door lock problem exists. He said at one point he was having to disect his switch to clean with a pencil eraser once a week! He ultimately solved the problem by installing a relay. Anyone ever tried that on one of our FJ's?

On that note...

 

[toy60]

If its 8 amp draw I have news for you

This was draining the battery overnight
nearly drove me mad!!!!


https://forum.ih8mud.com/showthread.php?t=40582

 

[MTFJ60]

baldredhead is right. connecting an ammeter between the positive battery terminal and a disconnected negative battery clamp can only read 0 amps because there is no path to ground. the ammeter must be connected in the circuit, between the disconnected negative clamp and the negative battery terminal to measure total amp draw. as wile e coyote said, you should definitely NOT connect the ammeter between the 2 battery terminals unless you want to fry your meter (well, most meters have a fuse, but either way its not a good idea).