JGard18

Simply put, my 87 GXL has no heat. The previous owner took it to the dealership, and they said it was the heater control valve.

I couldn't find that, so I figured I'd take a shot at what could very easily be the problem, the logicon.

Well, after spending hours resoldering everything, some problems have arisen now.

First the good. The LED above the foot button now turns on, it never did before. However, the LED on the temp control still does not turn on.

Here's the kicker, though. Now the air only comes out the front, and pressing the buttons changes nothing! Argh. Could I really have screwed things up worse than they were before? I thought I did a good soldering job.

Any ideas? Anything....? I'm kinda pissed now, because I've just lost my Friday night...

Templeswain

I heard of resoldering the logicons. And, well, you have guts man Cause resoldering old electronics is ultra tricky.
I hope you used flux.

Anyway,

I may have an extra one laying around and if you want it, its yours. You pay shipping. That is if I can find it.

The reason why you couldn't find the heater control valve, if my assumption is correct, is because it's being held captive by a Clan of Amazon Warroirs deep within the recesses of your dash.

I stripped out a dash from my 87 GXL yesterday and I could Identify it, and tell you if you have a snowballs chance in hell in defeating the Amazons.

JGard18

thank! PMed you. This thing is upsetting me, plain and simple

Icemark

I have rebuilt ones also available on my website.

But it is common to have the air mix motor go out and take out the transistors in the Logicon. The air mix motor is what controls the heat/cool. I also have brand new Mazda/ Imasen air mix motors available now. If the air mix motor blows, it almost always blows the transistor in the Logicon (and occasionally traces and diodes).

You should do a search on testing the Logicon and air mix motor. I have posted the testing procedure quite a few times. Before you buy anything you should make sure that the air mix motor is working correctly first.

The LED in the temp control should also turn on. The fact that it does not suggests that your re-soldering job may not be satisfactory.

JGard18

Thanks Icemark. I've seen the testing procedures, I believe... I'll look again, though. When I search on Logicon, only about 30 threads show up...I figured there'd be more.

Also, I'm pretty sure the heat motor thing is bad, but I just don't know how to get to it. It seems tucked way back.

And yeah, I guess my soldering job isn't good enough, but I'll tell ya, I've redone it three times now (just the faceplate board) whereas I did the whole big circuit board once, and I did about 50% of the little amp board.

Anyway, I'll wait to hear back from TempleSwain via PM, then I'll see what I need to buy from you. I've just checked out your store, and I'll at least be buying the heater mix motor. Thanks

JGard18

Well, Icemark, I bought the airmix motor and logicon from you...

Before I get those, I'll test the air mix motor that is in there now. I was just thinking, when I took out my current Logicon, there was a screw that was out of it's hole, and just rolling around. Perhaps that shorted something out?

I'm just hoping I don't have to deal with the air mix motor...that will not be a fun job.

Icemark

Yeah, I see a lot of broken screw holes and loose screws from the face plate section rolling around and blows out a transistor (and usually a couple of diodes as well).

Pretty much wastes the logicon heat/cool controls.

JGard18

well, that's comforting in the fact that perhaps the only problem I'll have is the Logicon, and not actually the air mix motor. But it's good to keep a spare on-hand, anyway, just in case

Icemark

well I did see one, that a loose screw put the air mix motor always on to the hot position and that burnt out the air mix motor as well, but maybe you'll get lucky.