Blower question (yep another one)

[frkoffalsh]

Vehicle is a '93 Grand Am SE 2dr. 5spd. 2.3L First thanks for reading this I found alot of threads regarding blower motors and resistors but am unable to find the answer to my specific situation.
Blower works fine on 1,2,3 and does nothing on 4.
Thought it was the switch so got a new switch and had the same problem.
Thought it was the blower motor got a new one still have the same problem.
I have continuity and voltage on both sides of the wire harness underneath glovebox (on all the wires including the orange one with is supposed to be speed 4) From what I understand from this forum and the schematic in the Haynes the resistors don't come into play on the high setting as it's under full power. So what's my next step or thing to check? Incidently the rear defrost also doesn't work but the button lights up when pushed and clicks like a relay sound. Hoping that's unrelated just thought I'd mention it. Really look forward to your responses cuz my brain ITCHES!!!

[GTP Dad]

Welcome to AF!!

The problem you are experiencing has to do with the ignition switch and the wiring harness that leads from it. You may want to search the Grand Prix forum as it is a common problem in the Grand Prix. This is not really a diy job so you may want to contact a dealer or mechanic to get it checked.

[frkoffalsh]

Hey gtpdad thanks for the welcome and reply! This forum seems awesome lots of experienced ppl on here reminds me of the r6messagenet forum for my motorcycle.

I went out again today to slug away at my blower problem. Traced the wire from the switch in the dash, under glovebox, through firewall into engine compartment and eventually to a silver box mounted recessed in the firewall. What is that box? It's located towards top and right in the middle. Has 3 harnesses that plug into it. Well I still had continuity from the switch to the plug of the wireharness but didn't mess with the mystery box so i bypassed it and made a fused wire( i "rigged it"). Hooked up to power (purple) of blower and all 4 fan positions work again. I just don't get why it would have to run through any electrical component (fuse,relay, potentiometer) if it's going to have full power anyway? Apparently one of those are in the box and it's failed.