Blower/AC/Defrost/Top/Amp All inop

[97gst_spyder]

So I just bought a new shell (96 GST Spyder), and swapped my engine and random things over.

The owner stated that the car needs a new blower, but the blower/ac/defrost(rear window)/top/amp are all inop.

There is zero power to all of these items. I have switched the internal fuse box out of my old car (97 GST Spyder - everything was working) and it didn't change a thing.

Also, I noticed that the defrost button does not even light up at night with the rest of the dash. I have checked all the connectors I could, all plugged in. Except, the blower motor has 2 connectors, a 2 pin (black and blue 8-10ga wires) and a 4 pin. Only the 2 pin is connected, the 4 pin is not, and I cannot find a connector on the harness.

Any ideas?

I have attempted to read the electrical manual, but I cannot figure it out on this one.

 

[PieEyedPiper]

At first I thought you were playing with things you shouldn't be in ceddy mods

Has the wiring or harness ever been futzed with prior to your ownership?

 

[97gst_spyder]

Haha, as far as I can see, everything is fine, untouched. The only thing i saw was a holder on the chassis harness behind the glove box next to the blower.

 

[97gst_spyder]

Any other ideas?

 

[Absit]

Check continuity across pins on the harness.
Try swapping out the ETACS ECU.

 

[97gst_spyder]

I swapped the whole fusebox, including the ETACS ECU.

We've narrowed it down to the blower/ac circuit. If I replace the 10amp heater relay fuse, and NOT turn the blower on, defrost, top, etc all work fine. As soon as I think about turning the blower on, it blows the living shit out of the fuse. To the point that all the lights i n the car dim for a split second.

 

[luv2rallye]

Sounds like the blower switch may have the short (which has been known to happen). Verify it's not the blower itself by unplugging it and applying a fused 12V directly (the all blue wire is the positive).

 

[97gst_spyder]

We bypassed the relay with a little jumper cable, the blower worked perfectly fine. All speeds, no issues.

 

[luv2rallye]

So your saying the relay is the problem then?

 

[97gst_spyder]

We changed that out with 2 other known good ones, also changed the fusebox which was also known good.

I keep looking at the electrical manual for the circuit between the power source and relay fuse and where ever it grounds but cannot figure it out.

Everything works minus the blower/ac system when I replace the 10amp heater/blower fuse. But once I turn the blower on with the rotorary switch, it blows. With or without the ac button pressed and with or without the car running.

 

[luv2rallye]

I still say it sounds like a faulty blower switch which has been known to short out just like you describe.

For the circuit, power goes through the 60A fuse, then a 30A fuse, then the blower relay, then the motor, then voltage dropping resistors (unless switch is in high position), then the switch, then to ground (so the switch supplies the ground when on). The other part of the switch, when not in off position, supplies power to the A/C switch.

There is also a 10A fuse that supplies power to the blower relay (to turn it on) and to the blower switch (which then goes to the A/C switch). If there is a short to ground in the blower switch when turned on (which is the known failure), it will blow this 10A fuse - so it's still a bad switch.

 

[97gst_spyder]

The rotary one is the one that fails correct?

 

[luv2rallye]

Yes the rotary blower (inside fan) switch. I updated my previous post so re-read it.

The rotary switch controls 2 separate circuits at the same time. The failure shorts pin 1 to pin 5 of the blower switch inside of it (when turned on) which puts ground on the 10A fuse. That is the common failure.

Or you have a short to ground somewhere on white-black wire coming out of switch pin 1. This would be very unusual though because someone would have to re-wire it wrong or it is touching ground somewhere.

 

[97gst_spyder]

Is there a way to rebuild or fix the switch?

 

[luv2rallye]

I seriously doubt it because it's likely something plastic inside has broke that glue can't fix. I've never had the problem but many on here have that have contacted me. But first see if it is broke. Unplug it, connect an ohmmeter to pins 1 & 5 and see if there's continuity when you turn the switch to any position. There must not be. If you don't have a meter just connect a light bulb to a battery through the switch's pins 1 & 5.

 

[97gst_spyder]

Ok, Ill look. I rather it not be the switch itself, its a pain to swap the whole assy out.

 

[97gst_spyder]

Ok, some good and bad news. Good is that I switched out the blower switch, all works there. Now for the AC part. I bought some Freon, the system was at 25psi after the car was running for over 5 min with the compressor on. I filled it to 50psi as per the can. The AC switch is green. But no cold air. I can hear the compressor clicking on too.

I swapped a whole HVAC assy from a 95 gst auto, and used the AC switch out of it also. I don't remember what AC switch went to my current shell, my old shell, or the donor 95 shell. The one that I tried first had 2 on positions. The second was the standard on/off. Could that hurt anything?

Any ideas?

Thanks again for everything!

 

[97gst_spyder]

I just changed the ceramic device out between the blower and ACCU, no change. I took apart the ACCU, and looked at the pcb. No issues that I can see.

 

[97gst_spyder]

The compressor relay was stuck... Swapped it out, all works!!!