J

I was doing a little bit of wiring work under the dash the other day trying to get my blackmagic electric fan to come on with the A/C so that it would cool the condenser. I eventually found a wire using a multimeter that was 12V when the A/C was on and 0V when it was off. Perfect! So, i spliced into it and ran it to the fan up front.

This worked ok, until i realized that the fan does something stupid. When the fan is tripped by some other switch (thermostat), it puts 12V onto the other switch wires and so the result of this is that when the fan would come on due to engine heat, it would make my A/C kick in!! Weird, but i didn't have time to fix it that night, so i left it temporarilly until i could get around to putting a diode on that line or something...

Today, for some reason, the A/C won't come on AT ALL. I've disconnected the switch wire that i ran to the fan so it is back to stock configuration, but no dice. The A/C light doesn't even come on at the push button swtich.

I have two possibilities. I have either burned out the dash switch somehow or i have blown a fuse somewhere. However, under the steering column there are no fuses related to A/C and they are all fine. The hood fuses have no problems either. It's probably the switch, but i just haven't had time to get a multimeter on it and check.

Any suggestions?

J.

enthalpy

Well - I haven't checked out this location myself, but after perusing the factory service manual - there is supposedly a fuse box on the passenger front side of your 4runner. I believe youhave to take the lower dash panel to get at it - but hopefully someone will chime in on this one.

I know this is not helpful at all - but from what I remember reading, that's where they put lots of the cooling/heating fuses.

I am at work, so I don't have the manual with me - I will double check when I get home though.

good luck!

Corey

iTrader: (1)

J, you might look at the CD manual that is online also.
http://www.net-impress.com/4runner/cd/

I am looking at the three air-con PDF files right now.
It mentions fuses in there somewhere, but I don't have time right now to sift through it all.

enthalpy

J,

Here are 2 pics showing the relevant info from the service manual. Of course, it doesn't mention how to get to it - but I think if you take off the lower valance/glovebox stuff, you can get to it.

Good luck!

enthalpy

J,

Here's the detail of the fuse box:

J

Thank you so much everyone, your contributions helped a lot!
Corey, that FSM site is AWESOME!!! One of them helped me to identify exactly what went wrong.

It turns out that when the BlackMagic fan is switched on from its own thermostat, it outputs 12V onto the other incoming switch wires (like the A/C compressor or a manual dash switch).

The wire i ran was connected directly to the A/C dash switch output and when this wire got 12V coming from the fan, it put the full 12V into the switch going the wrong direction. This didn't cause any problems at first, but eventually, it burned out one of the copper tracks in the switch.

I pulled it out and found this, so immediately called Toyota and their quote for that part was almost $40! For a push button switch!! Sheesh. So, i took my soldering iron, and used a small piece of wire to bridge the broken track, put it all back together and VOILA, it works again.

However, this time i went to radioshack and bought a diode and put it inline with the wire running from the A/C to the fan. Now, current can flow from the A/C to the fan (turning on the fan), but not vice versa...so everything is A-OK now.

Anyway, if you have a blackmagic fan, beware of this little problem, it could possibly smoke something more serious than a switch if you wire it wrong.

Thanks again everyone,

J.

Corey

iTrader: (1)

Glad you found that online manual helpful.

A member with a 3rd gen bought that CD off of Ebay last year to look at the detail of it, then uploaded it to his server.

Download the whole 20 mb ZIP file if you have not already.