awd dsm 1

Car is an 1989 GTUs, bone stock.

Wipers were working a few days ago on low speed only (no mist, delay, or high) now they quit working all together.

HVAC controls work intermittently (buying a different control unit to see if this fixes the problem)

Radio does not work.

Interior dash light dimmer does not work.

All fuses and the breakers appear fine. Sounds like electrical problems aren't anything new for the FC's, can anyone suggest to me where I should start? I do have a hanes manual for the car.

BASTARD

iTrader: (4)

the wipers are most likely the CPU... do a search .. there is a guy who rebuilds them ...I think his name is ICEMARK or something like that

ericgrau

iTrader: (1)

From what I've read FCs are prone to electrical problems due to a poor soldering job. I don't remember but I think there are 2 boards you can pull and resolder. It's best to resolder every joint, though there are guides to tell you what's what. Be careful not to fry any chips with heat from the soldering iron, because a new board is over $100. OTOH, if you go to get it fixed they'll just replace the board anyway. So worst case scenario you screw up, take it in and get a new board. I assume your car would still run without them. Or so I hope.

I haven't done it myself, I just read it's pretty easy (and free). Assuming you know how to solder, anyway. The Haynes manual has an electrical section (look for "chasis" not "engine") that'll tell you how to get to the boards. You'll need a steering wheel puller to get to one of the boards.

awd dsm 1

I've got a friend that can work on the boards if needed, where are they at and how do I get to them?

classicauto

iTrader: (3)

sounds like you've got a burnt wiper switch ad a burnt headlight switch.

For the heater I would first check the two breakers located in the cabin fuse panel by your dead pedal. If they are popped out, push them back and see if you get heat. If they are fine, you may want to try a new Logicon.

Icemark

Probably a bad wiper switch. If you want to try and rebuild it yourself: http://www.mazdamark.com/DIY_wiper_repair.htm

Or I can rebuild it for you. Or sell you an already rebuilt one.

Depends on what is intermitent to the problem. YOU DON"T want to plug in another unit if the problem is the air mix or mode motors, as you will probably burn out the new unit if either the air mix or mode motors has failed.

Probably a blown fuse

Bad light switch.

You need to meter the fuses, not just look at them.

And half the items you mention are covered in the FAQ for FC sticky thread found at the top of this section. Please read the FAQ for FC sticky trhead before posting.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/frequently-asked-questions-2nd-generation-rx-7-faq-fc-494667/

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awd dsm 1

Thanks for the help.

The logicon seems to shut off randomly, sometimes for the whole 1/2 hour trip into work, sometimes for just a few seconds. How do I tell if the air mix or mode motors are bad? When the HVAC is working, the fan only works on high, but the temp adjustment seems to work fine. A/C works fine when the logicon is on.

awd dsm 1

Is there any place that rebuilds Logicons?

Icemark

I used to rebuild them, but too many people were buying them and not fixing the car before plugging them in, so then I had to rebuild it under warranty again. Became a loosing deal to rebuild them so I stopped.

I do not know of anyone else that ever has rebuilt them.

My5ABaby

iTrader: (7)

What on the car would need fixed before plugging in the new one?

Icemark

Usually the air mix motor or mode motor, or blower.

The air mix motor is the most common, where the tempature does not change regardless of the setting. When the air mix motor blows out, it usually takes the Logicon fet out too.

So when I rebuilt it, and put a new fet in, it works fine until they plug it back into that same old air mix motor... as soon as they change the temp all the one one direction, the motor takes out the fet again.

So shipping costs money, new fet cost money, customer wants it done for free.

awd dsm 1

The only problem I seem to be having now with the heating and a/c system is that the fan will only work on high. Is that typically the logicon, or should I check other stuff. I do have a copy of the FSM, but I'm not very good with electrical systems...