I'm glad you have an answer. At the price of a reconditioned PBU, I might find a way to live with without a replacement. A toggle switch in the ground line will give you control over the compressor that the econo setting lacks.

Arthur has a suspicion that the problem lies in the evap temp switch. The switch is right on the edge of the default level and it's very possible that the switch will work with one PBU and not work with another PBU due to tolerances.

So, in the meantime, the system runs fine. I'll get an evap temp switch and see if I can figure out how to get it installed. Then, I'll attempt to use the original PBU and see if the new temp switch fixes the problem.

Yes, I certainly can put a switch in the ground line, if necessary. But, I'd much prefer that it function as designed.

Like that 'Ice Cube' relay mod?

j/k
But at nearly 600 bones for a reconditioned PBU, I will live with a switch...if, in fact, I end up ruling everything else out. If I were restoring this beast, it'd be different.

I think I can get a "reconditioned" PBU for about $250.00, but, I hardly want to spend that. I'll just roll the dice on e-bay for $75. per pop. I've got one extra one right now and I might just get another one to play around with.

If I have three of them, I might just open one up to see if I can resolder it.

BTW, that ice cube relay mod works perfectly. It takes the Klima and all of the inputs to the Klima right out of the equation. I wouldn't want to leave it there permanently, but, others have.

Concerning resoldering the PBU. stevebfl said that after '85 the PBU's are different and that the resoldering probably won't fix anything and could more likely make it worse as they're not tolerant to the heat of a soldering gun. However, you have an extra so give it a shot. I think mine has a loose solder joint as when I'm running the A/C, I only get air out of the center vents half the time. They stay off when they should be off so it's not an actuator problem.

Thanks
David

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