Dalgozy

1993 four runner 4x4 sounds similar to mine although my 10 amp ac fuse keeps blowing, i've disconnected ac switch, removed ac relay and unplugd th regulator board for the ac but it still blows instantly when fan is turned on.

wyoming9

iTrader: (1)

That should pretty much tell you you have a bad blower motor or a short in the wiring to the blower motor or the blower motor switch or resistor is shorted

Co_94_PU

iTrader: (-1)

He had a slightly longer description in one of the other posts. I think/thought it said the blower was functioning but the AC fuse kept blowing. Also had most of the AC system disconnected.

Power comes from the 40amp heater fuse, to the relay, then branches off one side to the blower the other to the AC fuse. I don't see any path thru the blower that would kill the AC fuse and not burn out the harness of course unless the harness is already burnt.

AC is kind of a non issue this time of year, at least in my world but I'll try not to hate on the warm ppl...

Had a short discussion with the OP via messages. I think they just need the heater, so suggested to unplug the rest of the AC system..

OK so in the dash is most of the guts, the amp, relay, and pressure switch are above and left of the blower. There will be three branches and plugs on a short branch off the dash harness. If you locate one of these you can trace it up to a connector that will disconnect three at once.

Dalgozy

The blower motor works fine at all speeds. heater works great, however I live in Galveston tx and want ac before summer hits! I have disconnected the ac switch, amplifier board, and relay and it still blows the ac fuse as soon as the blower is turned on!!

Dalgozy

I bought the 4x4 in this condition so do not know any past history.

Co_94_PU

iTrader: (-1)

You've disconnected it where I told you? And disconnected the switch in the control unit? If so you have an exposed wire some where not a faulty component.

Dalgozy

Is the single connector with the 3 connectors coming off of it accessible by removing just the glove box? if so, I will try today

Dalgozy

OK, I found the plug, unplugged it and same results fan works on all speeds but still blows ac 10 amf fuse instantly!

Dalgozy

i didn't disconnect the switch this time but it was in the off position.

Dalgozy

If its a wire issue would it be somewhere in the area of glove box or further up? I'm about to unbolt the fuse and relay holder and see what things look like back there. is that where you would start?

Co_94_PU

iTrader: (-1)

Test the switch for shorts to ground, if it's not the switch it's somewhere between the fuse and the connector that you disconnected in the glovebox.

blue wire with the white stripe.

Connect the ohm meter to the body, then probe that wire at the fuse at the switch and at the connector. The one with the least resistance is going to be closest to the short-circuit.

Dalgozy

The plug I unplugged is a 13 pin plug, just left of the amplifier. so if the fuse is still blowing, the short is in the wiring between the fuse and the male end of plug bolted to the heater/ac box, correct?

Dalgozy

UPDATE; I removed the ac/heater fuse bock. I found small white wire with black stripe coming off of relay to be melted, I cut off the initial black tape loom up to where it y's off, one direction the harness goes to the lft, the other direction through the firewall. I got it away from a couple wires up to the y in harness. I checked for continuity with all components disconnected, from the relay end of white/black wire to the female end of the 13 pin main connector and the wire is complete, however I'm getting several hits for ohming out on zero at several of the other points on the 13 pin connector. The white/ black wire doesn't seem to be melted at the end of the 13 pin female connector. I know I will have to remove the loom from the y in the harness to the left until the 13 pin connector to find other shorts. . My question is, does this wire y off into the the engine bay? Of course I will find out once I remove the loom. But also, what does this wire go to that could of shorted to cause the problem? Its not a shorted relay because I swapped relays with the same results. Its possible something else in the loom is shorting to it and caused it to heat however, everything else dashboard wise works other than the light for the heater control, which I haven't checked out yet. Any suggestions on where short could have begun? and where does white and black wire lead to???

Co_94_PU

iTrader: (-1)

White wires with black stripes are ground wires, in this generation, that means they connect directly to the body, chassis, or negative terminal of the battery.

Did you get that AC switch in the heater control panel pulled and tested yet? This is the most likely source of a short circuit, and it's the only thing still connected to the AC fuse intentionally. Behind the center section of the dash is also the most likely spot for something have gotten pinched, by say a stereo installer for example.

...
"My question is, does this wire y off into the the engine bay?"

Yes most likely the ground wire runs into the engine bay.
...
"But also, what does this wire go to that could of shorted to cause the problem?"

The AC switch in the heater control panel. Specifically I'm guessing the light burnt up and is shorted to ground.
...
"Its possible something else in the loom is shorting to it and caused it to heat however, everything else dashboard wise works other than the light for the heater control, which I haven't checked out yet."

It could simply be a combination of Everything it is the ground supply for AND the bad heater control panel AC switch that over heated it.
...
"Any suggestions on where short could have begun?"

The only intended connected item is the AC switch in the control panel. If there is no fault in the switch there must be an exposed or pinched wire.
..
"and where does white and black wire lead to???"

It grounds to the body, either the kick panel or inner left fender. I assume.
.

Dalgozy

I still have the switch in dash, I assumed since I unplugged the 13 pin connector, that would isolate everything. I will pull it tomorrow and check it. It also has a aftermarket radio so you could be correct on that also. Im assuming also that if I pull the ac switch out and put in a 5 0r 10 amp fuse and it doesnt blow, that the switch must be the problem, Is that a correct theory? and how would I test switch?

Dalgozy

ok, I pulled switch and it seems fine. it lights with dash lights and the two end pins are on and off and are working correctly, on and meter zeros out off and ots open. also open from any combination of pins othe than on position in the two on one side for on/ off, loooks like I need to pull dash bezel and radio to look further.

Co_94_PU

iTrader: (-1)

Can someone please confirm for me the 93 era AC switch doesn't have a backlight that toggles with the dash lights.
..Pretty certain it doesn't but not at home to double-check.

Dalgoz,
With plug #A14 (AC switch in the control panel) disconnected, it still blows the fuse correct?
It doesn't look like it's going to be a simple part malfunctioning that you can just swap in a good one. The light inside the AC switch should only come on when the switch is in the on position, the fan is set to something other than off, and the ignition is on (key in run position).

The diagrams and locations are in the PDF files I attached above.

​​​​​​
There are two plugs you'll be checking,
IG1 (behind the glove box) connector.pdf page 35 shows pin numbers.
A14 (AC on/off switch, behind the controls) aircond.pdf page 172 shows pin numbers.

Diaconnect the battery's positive terminal.
Remove the AC fuse.
Make sure these plugs (IG1, and A14) are both disconnected.
Set your multimeter to continuity mode.

Now locate pin number 11 on the vehicle side of the IG1 plug it will have a black and yellow wire. Place the red lead from your multi meter into IG1 pin 11.

Locate pin number 5 on the vehicle side of the A14 plug it will also have a black and yellow wire. Touch the black lead of your multi meter to A14 pin 5. Your multi meter will sound a tone.

Next locate A14 pin 4, a white and black wire. Touch the black meter lead to this. Did it sound a tone? If it sounds a tone (continuity) you have located a direct short to ground and this wire needs replaced.

..Next..

Locate IG1 pin 9, blue and white wire. Insert the red lead of the meter.
Locate A14 pin 6, blue and white wire. Insert the black lead of the meter. You should have continuity.

Now put the black lead back into A14 pin 4. You should not have continuity. If you have continuity this wire needs replaced.

​​​​

Co_94_PU

iTrader: (-1)

Please re read your posts before you submit them. Typos, bad autocorrect, and lack of punctuation make it even more difficult to understand and visualize what you're trying to communicate with out being able to see what you are "pointing at"

Merci, CO

Dalgozy

`OK, so following your advise on last post, the pdf file did not show a 1g1 plug. However I did find a similar plug that was plug as part of the 3 to 1 plug. upon testing, I found a open circuit between the pin 9 of 1g1 and pin 6 of a14. Your advice would be to replace this wire. I don't like to second guess anyone, but, in this case I am. Something has caused the white wire with black stripe to melt and constantly blow 10 amp fuse. A open circuit wont cause this. Only a short will. I have completely removed everything from radio, relays, everything that could of caused this wire to over heat. I even ran a wire to compressor clutch with no issues.I strongly know that I have to cut into loom and find everyplace the over heated wire has melted into another and remove the burned wire and replace, and insulate other wires and then figure out the cause of the problem. I am an electronics tech by trade but with health failing, I've forgotten more than what I've learned. I have concluded what you have said is correct that the problem lies between the fuse and the ac switch. I am honestly leading to a shorted diode or transistor in the amplifier board that initially caused the problem. I appreciate all the help and think you have led me in the right direction to find faulty wiring however the underlying cause is the most important part I now need advise on. Everything we spoke of checks out ok however the amplifier hasn't come up as a cause. If I'm going in the wrong direction, please let me know. PS. If my spelling or grammar is not correct either, please let me know.

Charchee

I'm also a little curious if your switch is backlit when the dash lights are on. I'm pretty sure it should only come on when the switch is closed and the fan is running. Can you confirm that the switch does light with the dash lights while in the off position and fan off? What about with the dash lights, switch open (off position) and fan on?