Parasitic drain and weird relay issue

[shadetreemechanic]

I hate electrical issues and this is doing my head in guys, please help me.

So this issue started out months ago with my blower fan that stopped working all of a sudden. I traced it to a dud blower relay and blown/melted fuse 9 (some twit, probably me, stuck a 15A fuse in place of the 25A one) and once swapped for a new relay and the proper fuse the fan has been fine since (more or less).

Recently it's been randomly cutting out then by playing with the fan controls 1,2,3,4 it springs back into life. I thought the control unit's going out.

Well here comes the kicker, recently I came outside of a cold morning to find the battery dead. Fair enough I thought, that battery's been in there for donkeys years. So I put in a new battery.

Fast forward to COVID and I had to hook up a battery charger since the car wasn't being used much anymore. This is when I noticed the brand new battery was running down far too soon. First indication was the battery charge indicator's gone dead. Slapped on the multimeter and sure enough, low volts. On goes the charger. After a couple of days, multimeter confirms battery ran down yet again.

So I then did a parasitic draw test, lo and behold it's using 160mA with everything off. Bugger...traced it back to the blower relay, thought it had stuck or something. Nope relay is seemingly ok but I now find that the 85 and 86 relay coil connectors have 12v across them. WTF?? Blew the 10A fuse in the multimeter when I bridged those coil connectors, I thought that was a low amp circuit? Ignition relay also has same 12v across the relay coil inputs (all this with the key out of the barrel).

Ignition barrel switch seems fine, I just pulled it apart and the ign. relay still has 12v across the coil.

Does anyone have a clue what's going on? This is driving me up the wall lol.

 

[Immortality]

A lot of stuff is negatively switched so you will see 12 volts at the relay. Is this a climate control system?

 

[shadetreemechanic]

Ok, thanks I wasn't sure if it was normal to have 12v at the relay. No it's standard AC only, not climate control.

 

[Immortality]

Ahh bugger. I don't know much about the standard AC.

First things first though, it pays to find a wiring diagram.

 

[Immortality]

Not sure if this is correct but see if it correlates with what you see in the car.

 

[shadetreemechanic]

Yeah of course, I have these diagrams you posted but none of it makes sense. For example, notice in the one I attached the blower relay is part of the climate control only circuit but it's used for the standard system for sure.

This is what I drew up last time when the fuse melted (could be wrong though?)

Battery->Fuse 9->Control Unit (speeds 1,2,3)->Fan speed resistor
Battery->Fuse 9->Control unit (speed 4)->Blower relay

Edit: Uploaded the V6 manual pdf diagram it's clearer and is the same as the auto.
Edit2: My fan speed resistor speeds 1&2 are dead, common issue and I've just lived with it.

 

[shadetreemechanic]

Also, when the blower relay is unplugged the parasitic drain disappears. Initially I thought the relay was fried internally so I bought a new one, interestingly for a few seconds that relay was plugged in the drain was gone then "click" relay turns on by itself and drain is back (all while i was holding the multimeter contacts to the battery).

Now the new relay behaves just like the old one which is itself new-ish since the time the fuse melted.

 

[Immortality]

Blower relay or fan relay?

 

[Immortality]

You say speed 1 and 2 don't work?

Looking at the wiring diagram I posted speeds 1,2 and 3 work via the fan resistor, this works by dropping the voltage to the fan so it turns at a reduced speed. Speed 4 is via the fan relay and gives full voltage/current for full speed on the fan. I wouldn't be surprised if the faulty fan resistor is causing the problem somehow. Unplug the fan resistor and see what it does.

 

[shadetreemechanic]

Blower/fan same thing, yeah that's what I was gonna try but I need to get a new fuse for my multimeter tomorrow before I can test again. I already pulled the cowl off the windshield and yanked the fan resistor out lol