DaleClark

iTrader: (55)

Hey everyone -

Driving in the car today with another guy from work, and the AC is at position 3 (hot day!). Suddenly, the AC stops blowing - no air coming out. I play with the switch, and positions 1-3 don't do anything, but 4 works as advertised. Hmm.

I do have a PowerFC, so at first I thought I had finally caught the dreaded PFC AC problems (I have NEVER had an AC problem with my PFC). But, that's normally on a certain position, like 3, and not 1-3.

So, I dig out my trusty shop manual. There is a resistor for the fan blower that's actually in the air path to keep the resistor cool. There are 3 "levels" of resistance - this steps the voltage down from the maximum 12v to slow the blower down so you get differing speeds. When you're at positions 1-3, the voltage goes through the resistor, but at position 4 the full 12v goes straight to the blower motor for maximum speed.

So, there seems to be something up with the resistor. Resistors don't typically go bad, so I figured the connector came loose or something. Using the shop manual, I found the location of the resistor - it's on the blower motor under the passenger side of the dash. If you get up under the dash, you'll see wiring (most of the wires are blue with different colored stripes) going to a 4-wire black electrical plug. That plug is the resistor - it's held into the blower case with 2 screws. I popped mine right out.

The contacts where the plug attaches on the resistor were VERY dark and corroded looking. I shined them up some with a small file, reassembled, and I'm back in business. I'm going to call Ray at Malloy tomorrow to see how much a new resistor runs - if it's cheap, I'll likely replace it with a new part.

Anyhow, hope this helps somebody down the road .

Dale

Tim Benton

iTrader: (1)

Best thing that happened to me, Dale getting an FD. Thanks again for the helpful tip.

Tim

grinn253

Thanks for the info!

Edgardo

Fritz Flynn

iTrader: (263)

That's funny and very true

DaleClark

iTrader: (55)

Hehe - thanks!

Funny thing is I bought a Lexus SC300 about 2 years back with the intention of really getting into that car. I got active on the Lexus forums, did some writeups, etc. One of the mods got into a big pissing match with me (long story) and I headed out of there. VERY different community, BTW. Anyhow, I told him that he really made a bad mistake running me out of town . So, the FD guys win!

Dale

WaLieN

I agree. I enjoy Dale's write-ups.

REAmemiya FD3S

That's exactly what i said a couple months back when he first posted the FC thermoswitch idea. I currently don't have any problems with the AC blowing in any of the positions, but at least i know how to fix it now if it ever happens.

Thanks again Dale!

Fritz Flynn

iTrader: (263)

Hell most of my cars don't even have AC but this kind of post is so cool it makes me wanna go foot loose baby FOOT LOOOOSE

twinturborx7pete

iTrader: (3)

needed this cuz my fan3 doesn't work!

DaleClark

iTrader: (55)

BTW, talked to Ray today and got a new resistor pack coming - it's $36.94 for the resistor. I didn't get the part number, but if you ask for the AC blower motor resistor pack, he'll be able to look it up.

He said that it's a common service part for other cars, but he really hasn't sold any for the RX-7. So, I don't really know how common of a problem this is.

Anyhow, I got a new one coming - I'll get old and new part pics when it's here.

Dale

twinturborx7pete

iTrader: (3)

ever get the part in?

DaleClark

iTrader: (55)

Yep, sure did. It was about $30 or so from Ray at Malloy - I took pics for a writeup on it, should have that done soon.

Just cleaning the contacts did get my AC going, so really if you have this problem that's probably a good place to start. But, I wanted to go ahead and put a new part in there because I'm wacky like that .

I'll try and get the writeup done this morning.

Dale

7racer

My mechanic actually thought of this very issue. I have a PFC and 94 touring. Never had the AC issue until after the rebuild and installing a new wiring harness.

After the rebuild, the dreaded no AC with fan switch 3 showed up. Replaced the resisitor and....NO AC on 2-4!!! It seems the PFC is very sensitive on the grounding. I think replacing the resisitor will help some people but others might find that they need to ground (sorry don't know the specifics of the wire my mechanic was talking about)

DaleClark

iTrader: (55)

Writeup is done, BTW -

http://www.clubrx.org/default.asp?id...ntent=59&mnu=5

I haven't had ANY AC issues with my PowerFC. Not even a hiccup, knock on wood. Others have found the root of the problem seems to be the actual fan speed switch - cleaning the contacts or replacing it seems to help.

Dale

FurryRoadkill

wow, thanks dale.


This is the third write-up you've written that has been useful for me.

White94RX

Resistors do fail, at least on BMW's. We replace blower resistors all the time.

I've got a PFC too, and I've got what seems to be the most common problem: Fan works on all speeds, but only runs the compressor when on speed 1 and 2.

Derekismoney

i had the same problem last week. Gonna call ray now they wanted $112 for that little resistor from the dealer haha. I didnt know anyone made it aftermarket.

Sled Driver

iTrader: (9)

What I appreciate about all Dale's write ups is his troubleshooting.

No guessing........... half *** fixes.........short cuts or redesigns to try and save a dime.

Figure out what's wrong. Verify the fault. Replace the part with the proper part.

You, my friend, are truly a mechanic. I wish I worked with more like you. My life would be easier.

namasan

Anybody have Dale's writeup on this? clubrx.org is down