Can anyone tell me if it is normal to have four wires going into this blower fan connector and only three coming out? Maybe one melted. I keep blowing the fan fuse whenever I move the a/c selector lever out of the off position, unless I unplug this connector going to the blower motor. Then, the fuse doesn't blow (but then the blower doesn't work). I already replaced the 5 lead switch and connector mounted on top of the a/c-heater selector lever in the cockpit. That connector was fried too.

Thanks!

 

Sorry, I may have posted this in the wrong section if the "cooling" section also covers heat and a/c (I didn't realize it may have). Will the moderator please move this post if this is the case. Thanks.

 

I have a 92 z28 350 car too, and it looks like the 4 in 3 out is correct. I would advise reworking that connection, however, because it looks pretty bad and you are having issues. I have included a link to a picture of the connection on my car for reference. If it doesn't open for you, send me a private message with your cell number and I will send you a picture mail of it. Good luck.

https://plus.google.com/photos/10674...OupkpvYo43m4gE

 

Thanks for taking the time to link the picture. I will redo the connection. Hopefully that is where the short is occurring. Aside from that I'm not sure where it could be.

 

Pretty much every connection could be an issue. After so many years you get dirt and corrosion issues which cause problems.

 

Thats the way those connectors look. they are loaded with some kind of grease from the factory.
Make sure your blower motor is good. when they go bad they draw a ton of amps and cause wiring probs.. clean your blower motor ground also.

 

The blower motor works okay at all speeds, but I have to disconnect the center wire of the 5 wires going into the a/c-heater selector switch to run it (see link).

If I connect this center wire and move the selector lever out of off, the fan fuse will blow.

https://docs.google.com/open?id=0B-W...Q5ZTVkYzE2ZTNk

 

This is where a factory service manual from Helm can help ya..

 

I have the factory service manual from Helms. I bought it back in 1992. Trying to use it to troubleshoot a short like this is like trying to understand the tax code.

 

I tried to trouble shoot the 25 amp fan fuse blowing. First, in the engine compartment, I unplugged the a/c relay, the plug that goes into the blower motor and the 4/3 prong connector. I also unplugged the a/c compressor connector to rule that out as well.

https://docs.google.com/open?id=0B-W...M1OTZkMmZmMTRj

I start with a fresh fuse and turn the ignition on to energize the a/c-heater selector. I turned the a/c selector to max and the blower on. Nothing happens and the fuse is still okay.

When I connect the 4/3 prong connector in the engine compartment, the fuse blows. So, whatever the wires in that connector lead to must be the problem, because I've isolated the blower motor, the a/c compressor and the a/c relay.

Before I connected the 4/3 prong connector, I measured 12 volts at the center lead (red wire) from the 3-wire side.

Anyone know what the wires in this connector in the first post above lead to? They go into a harness and I can't tell. Thanks.

Addendum: The factory manual says that in the high position of the bower fan, the blower resistors are bypassed and the power comes right from the battery through the fusible link to the blower motor. I even tried moving the selector lever to max with the blower switch already in high and it still blew the fuse. At this point I have to get more fuses.

 

Tax code ! thats funny!
Yes it can be a nightmare trying to read that.
It sounds like maybe the big red 12 volt wire (blower fan high speed) is whats giving you problems.
Now you will have to learn how to read the wiring diagrams to find out where that lil guy is routed.

 

Here's the schematic. It doesn't help much.

 

See all the C102, C105 type numbers? those are connectors, now flip to the component veiw pages and you can findout where they are all at.
You can also find out where all those relays, fuses and switches are located so you can do continuity testing on sections of your wiring without ripping it all out of the plastic tubing..

The tuffest thing about the book, once you have it, is learning to use it properly.

does your car have a aftermarket radio? have you pulled your HVAC unit out to look for a short on the fan switch "high" postion wiring?

 

It's had an aftermarket radio since 1993. I replaced both the blower speed switch and the a/c mode selector switch (and connector) sometime in the late nineties, but I will use the Helms manual and do the checks again. I just bought a blower speed switch from Rock Auto, so I'll throw that in this week. I need to get more fuses before I can do any troubleshooting.

I had a problem with the same melting connections in the past, but it was so long ago, I can't even remember how I fixed it. I guess that's how you know you've had the car too long, or maybe I'm getting too old and my memory is failing. Thanks for all the input, TTOP350. I'll let you know how it turns out.

 

I replaced the blower speed switch and now I'm in the process of checking the resistance values for the blower resistors with my digital meter. The manual refers to terminals A, B, C and D, but the part itself is labeled 1 through 4 (see picture). If I presume 1 is A, 2 is B, 3 is C and 4 is D, I am getting significantly different figures than the manual.

Here's what the manual calls for and what I'm actually getting:

A & C: Manual calls for 1.5 +/- 1 Ohm; I get 1.2 Ohms (within limits)
C & D: Manual calls for 0.7 +/- .5 Ohms; I get 2.9 Ohms
D & B: Manual calls for 0.2 +/- .1 Ohms; I get 3.7 Ohms

Does anyone know if the letters correspond to the numbers?

I measuring the resistance at the spade terminals with the part out of the car and disconnected from the electrical connector.

 

If your blower motor is only blowing fuses in the High position you don't have to worry about that part. High speed uses its own power wire (I think).
Someone correct me if Im wrong

 

I found the problem! It was a wire going to the AC compressor. I traced the 5 wires from the AC/Heater selector switch through the firewall to the engine compartment. This led me to the green wires in the picture. One wire was hidden and smashed against a support brace when I put the heads back on. The cuts in the wires at the connector were mine for troubleshooting and I taped them back up. That's how I discovered the short on the wire below. The manual was really no help because it didn't break down the individual wires in the schematic.

As for the blower resistor, I think I will replace it just in case it's bad. It's only a $10 part.

Thanks again, TTOP350, for the time and help on this.

 

Its always something easy ! lol congrats! now go and enjoy your non fuse blowing Max A/C machine !!!!