A/C Aux fan not running, yes another post, yet a different scenario

[Rousan_e30]

Hello guys,

i know this might be the millionth post about this problem.

I’m running the A/C fan just for A/C use, I’ve got a separate fan for engine cooling.

The aux fan was working wonderfully, i press the A/C switch the Compressor clutch engages and the A/C fan works.

I have the resistor on the fan removed, and the fan wired to the Normal speed relay wire, so the ac switch can trigger it.

the problem suddenly happened, now when i press the Snowflake A/C button, the compressor engages but the fan wont work.

I've looked at multiple threads and took a look at the electrical diagram for the low and high speed relays, and noticed that there’s a diode before the K1 relay. I lifted the fuse box top section to find out the diode was fried and shorted to a Green/black wire,

i cleaned all of the wiring and replaced the diode so nothing is shorting now hopefully, still the aux fan not turning on when i press the ac button.

if i jump the 87 and 30 pins on the K1 relay it works, so it’s not a ground issue.

what i found weird is that my k1 relay has the Wire coming from the diode on pin 85 not 86 which is different from the original diagram.

I jump the temperature switch wires one to another, but still nothing works.

my fuse box is all original, and hasn’t been tampered with at all.

what do you guys recommend that i do?

thanks

[e30partsonline.com]

Check the sensor and wiring on the radiator.

[Rousan_e30]

No problem with the sensor nor the wiring

[uturn]

Check the fan.

[ADEN]

Try to use the wire that comes from K6 in the temperature switch area (high speed fan relay) instead of K1 to trigger your fan.

Maybe K1 bridge inside the fuse box burned.

[ghrays]

I had the same problem, the aux fan would only intermittently turn on when depressing the AC dash button. I finally traced the issue to corrosion in the chassis three-pole plug housing that connects to the aux fan harness plug housing next to the driver’s side headlight . By removing the old, corroded receptacles and soldering into the chassis harness three new 2.5 mm snap-in water-tight receptacles, it solved the problem .