Is it normal for your A/C compressor to kick on and off every few seconds when your in "Defrost" mode? I wouldn't think so since it's normally considered a heating operation...yet when I slide my selector **** all the way to the right to defrost, it engages and disengages my A/C compressor clutch every few seconds, like it would if it was low on coolant. Normal?

Also, when I turn my blower motor all the way to high it shuts everything down. Blows air fine on all three other settings. But no matter what mode I'm in, be it Heating or A/C, the "high" setting does not work. It's been like that as long as I've owned the car...and I don't even know where to begin troubleshooting...any suggestions?

 

Yes it is normal for the AC to do that. The reason is, the AC dehumidifies the air, as well as cooling it (before it can cool it, actually); which improves the effectiveness of the defroster GREATLY.

Look at your blower motor. You will find that it has a purple wire, and a black wire. The purple wire finds its way to a little box mounted on the evaporator housing, which is the high-speed relay. What this does, is to send power from the resistors to the blower motor, in the 3 lower speeds; but in the highest speed, it replaces this, with a high-power source of 12V directly from the battery. This is so that the much higher current of "high" doesn't have to run through all the wiring and the switch in the dash and all that. It's possible that the relay could be bad, but it rarely is. At that relay, in addition to the relay, you will find a couple of small wires and one big fat red wire, which is the 12V feed. Follow that wire toward the driver's side of the car. About right directly above the pass side valve cover, you will find a connector. Attempt to unplug it. More than likely, you will find that it has burnt to a pile of ash. It always does. It's totally inadequate, and burns up in EVERY SINGLE ONE of these cars, if the high speed blower gets used very much. Cut the red wires, and install a set of HEAVY DUTY slide terminals; not the normal little weenie ones, but the BIG THICK HEAVY kind. I'd give about 95% odds that that's what it needs.

 

I'm with Stupid ^

 

Wow, thanks a lot guys. Now that I think about it, kicking the compressor on makes a lot of sense.

I never realized that the blower connection was such a widespread problem, I just pulled that E.S.C. (haha, props vader) connector apart and it was burned to a crisp. You guys just saved me a lot of time running through wiring diagrams, lol. I owe both of you one one.

 

The level of stupidity you can find on these boards is amazing sometimes!!!

THe next thing that's going to happen to your system is, there's ANOTHER one of those connectors in the power feed to the AC control head. Since you've been using your blower motor on the next-to-highest speed, that one has been stressed to the max; and probably isn't far behind. When it goes bad, ALL your HVAC electric functions cease.

If you pull the control head, you'll find a plug that plugs into the "mode" switch. It has about 5 wires or so, not a real huge connector. One of its wires is brown, and kind of goes off under the dash all by itself. In that wire about a foot upstream from the control head, you'll find the connector; and it too is most likely burnt to a crisp. It's OK to use just regular blue slide terminals on that one; just make sure to use the fully-insulated ones, so it doesn't short to anything and blow fuses.

 

Hey, I kinda resent that. Do you call all the people you help stupid? Or am I the only one to gain that privilage.

And F.Y.I. - My system does NOT have a fusible link there. It actually has an unbroken wire all the way to the firewall. I am well aware of what those are. I was simply asking about frequent problem areas so I would know a good starting place to troubleshoot. My actual problem was the the restistor connection for the constant 12v feed. That's what I was refering to at my E.S.C. connector. I could have flipped open my reference manual, read wiring diagrams, gone from point to point with a v-meter, and found it that way. But then what's the point of the boards?

And under the dash is fine. Thanks for the note on the link though. If everything goes out I'll keep that in mind.

 

Is the AC control head visible in the pictures Vader posted? If so, would you please describe where it is? Thanks - Adam