Auto climate air amplifier question (1 Viewer)

[MKS]

Hey guys, have owned my '97 40th Anniversary for a few months now and in that time the climate control has never worked at all. PO said it used to work and then started intermittently working and then died. Looking through various threads on here and seeing that other people have had the same issues as mine (no A/C, heat or fans, middle row of buttons dead)... I decided to have a look at the AC Amplifier. Upon removal of the box, I saw some small amounts of corrosion on the pins and figured I could clean that out and maybe it would work again. Then I pulled the circuit board out of the box and found this:

Yeahhh...this thing is complete junk. I've seen pics of these boards with light corrosion on them, but never like this...may as well have been pulled out of the bottom of a lake. I have no idea how it got this bad, must have had one hell of a windshield leak at some point as I found dirt and other junk in the bottom of the box too. Anyway I'm fairly certain this thing is not fixable at any cost and so my only option besides a manual conversion is to buy another one and these things are getting hard to find. I saw one on Ebay for $300 (looked a bit sketchy) and Cruiser Parts has them for $450. Figured I'd ask here and see if anybody has any other thoughts about where to get one of these. I didn't see any Cruisers listed in my local salvage yards, may look into that some more. Other than that I don't have too much to go on. The part# on mine is 88650-60212. I've seen the same white box with a different # but I'm unsure if they all interchange. Any info anybody has will be helpful.

 

[grizzy]

Eureka.....After checking every electrical connection, fuse, relay, circuitboard, cleaning with Isopropyl Alcohol going to 3 dumbfounded mechanics, I read your thread and decided to finally check the AC Amplifier. Mine looked exactly like yours rust, water stains and dirt. I replaced it yesterday and the entire HVAC system now works. I was ready to donate my lx450 and/or push it off a cliff but now it has new life and I can regrow some hair that I pulled out of my head and go into rehab. This drove my mechanic crazy as he wasted over ten hours trying to figure out why the hell the fan would not go on, simple right? I yearn for the good ole days when there were no freaking circuit boards in a vehicle. The Lexus dealership mechanic even checked it and couldn't figure it out. Evidently the leak from the sunroof drains right into this damm AC Amplifier.

 

[Mandrake]

Hi there. Aircraft electrician here. Avionics don't rust like that, but I've dealt with similar issues on far more complex components, and it's not a big deal, really. First, that appears to be rust from a ferrous metal, and the metals used in circuit boards are almost always non- ferrous, or only very slightly ferrous alloys; either way- not enough to create a mess like that by itself. I suspect the corrosion you see may be from the metal housing it was in rusting and not the board itself. I do see some areas that may have let the magic smoke out after being shorted out due to submersion in water.

I'd have to see it in person and under a magnifying glass to say for sure, but that looks salvageable. I don't see any surface mount parts, so it'd just be a matter of cleaning the corrosion up, repairing any traces and maybe replacing a few components if the corrosion is bad enough on their contacts. Most of those diodes and resistors can be sourced for next to nothing if not free as a sample from various sources.

If you want, send it my way and I'll see what I can do. Shoot me a PM to work out the details. Fair warning: Without seeing it in person, I cannot guarantee anything. It may turn out that it is indeed unsalvageable.

 

[MKS]

Thanks for the reply, I am indeed going to try cleaning it first before I shell out a bunch of money for a used one. If I get nowhere with it and you'd like to take a look at it, I might be willing to send it over you as you're only in Utah. What is the best thing to use to clean it with? Just baking soda and water mix, or something more substantial?

 

[Mandrake]

90% isopropyl alcohol and a q-tip.

I thought about this a bit, and if @grizzy still has the bad one, I'll paypal a ten spot to cover flat rate usps to get it here for me to dissect and fart around with. I suspect these failures may become more common, and if I can repair the boards for a nominal fee, it may be a cost effective solution to rolling the dice on a used one.

 

[shocktower]

Deoxit best thing for stuff like that

 

[george_tlc]

I'd use isoprop on it - locally I can buy 99.9% stuff (electronics store). Toothbrush and isoprop should hopefully remove a bunch of the contaminants. The boards should have been conformal coated at the factory - would have saved a lot of the oxidation/corrosion on the board.

Maybe even run it through an ultrasonic wash (distilled water) and see what nasty stuff can be removed first.

Hopefully the big IC (possibly some custom device or pre-programmed uC) is not damaged.

cheers,
george.

 

[Mandrake]

Question: if this board got plugged into a truck that didn't have auto climate control, would it work ad designed, or are there other components in the automatic hvac systems not present on the others? I'm just thinking down the line for testing purposes as I don't have auto hvac in mine and none of the local guys do either.

 

[MKS]

I'm fairly certain you can't plug that box into a manual climate control system. I don't believe the electrical plugs for it are even there. The two systems are different for sure. It would be a challenge to know if you've fixed it or not, without some way to test it.

 

[Mandrake]

Well, damn. That changes things a bit, then. If I have no way to test, then there's really no point.

 

[grizzy]

Update. I was lucky to get an AC Amplifier box from the local Toyota junkyard(for free) as the dealer didn't think it was too important so he let me have it. My rig is a '97 lx450. Also does anyone know why the DIFLOCK light is always on when in 4WD . I am going to swap the switch(DIFLOCK mod) and see if it fixes that. I had a 93 FZJ80 and it seemed more like a tank than my LX450 with OME 3" kit(rollover prone?). I will post a pic of the AC Amp ASAP but now I am afraid to let go of part as it may be very hard to get. It would be nice if you could borrow someone else's AC Amplifier, plug it in and see if yours works or fixes your problem.