AlaskanLS

Man I am keep forgetting to inform you. Please check for loose fuses in the fuse box that will cause on and off scenario for the AC. Some times people insert brass metal to take connection from the fuse box for other instruments that will make the fuse loose inside the socket. I had a problem my climate control fuse wasn't blown but it wasn't turning on the climate control unit. I found out that fuse was not passing the current for climate control. So I disconnected the battery and with help of tweezers made the socket for the climate control fuse more tight. And it started working after that.

Spartan536

Not that I remember, however here is the thing..

When I first got the car, within a say the A/C - Radio fuse blew, my mechanic told me the unit was dead, I ended up sending the unit out to Tanin, while it was uninstalled from my car I decided to look at the fuse box on the drivers kick panel... BAM blown fuse, replaced it and the radio and mirror control came back (all 3 are on the same fuse).

Tanin told me my control unit was working perfectly on their diagnostic table, I still had them replace the old LED's which glow green with new white LED's, but kept the OEM green color for the indicators (they were replaced too, in fact ALL LED's were replaced).

Moral of the story, I never really got to test it out before it was sent out for repair... still pissed at my mechanic for that, the look on his face when I told him it was the fuse that had blown caused the issue was priceless.

I have since replaced the fuse with the proper Japanese type fuse picked up at ORielly auto parts. The fuse has not blown again since I replaced it, and yes I did make sure to replace it with the same amperage fuse as the manual indicated.

AlaskanLS

Two things to look into. First make sure the back harness of the climate control don't have a loose wire that is causing it to turn on and off. Secondly check the fuse box to make sure that the fuse is not loose and sitting firm in the socket. There is loose wire somewhere that is causing it to turn on and off. Follow the climate control harness all the way to fuse box if you can and look for any wire that is cut and barley hanging. Climate control also has a fuse inside the engine bay. Make sure that radio fuse and all other fuses in the engine are sitting tight in the socket.

AlaskanLS

There maybe a fuse with rusted prongs inside that engine bay which might be causing this fault. Look for old rusty fuses also. Replace them regardless even if they are working. Check all the fuses prongs for rust under the kick panel as well.

AlaskanLS

Check the back pins of climate control where you insert the harness and make sure no pin is wobbly or loose.

Spartan536

I uninstalled and reinstalled the Control unit myself, being an IT hardware professional I made sure all the contact pins were straight and were in good working order, they passed visual inspection with ease, they looked brand new, no signs of corrosion or arcing.

The wiring harness that it connects to seemed to be in good condition as well, I did not observe any pulled wires or damage, when reinstalling I did make sure to hear the clips connect, they do make a nice audible sound to indicate they are latched into position, and there is no way to plug the wrong one into the wrong socket, as they are keyed (a nice attention to detail that I thank Lexus for).

I will check the connection for the A/C - Radio fuse in the kick panel just to be sure, pretty sure there is no rust there, as for the engine bay, I will have to look into that one.

AlaskanLS

Since you have spent so much money on this car. I really feel sad for you that the things u spent money on didn't fix your problem. My next suggestion is please buy a used climate control, look for cheaper one that has busted display and try it in your car to make sure that your car's original climate control has no hardware issue. There are many climate control switch boards on ebay for round about 50 to 80 dollars. You can sell it anytime once you make sure that climate control switch is fine. I wish you were closer to me, I would have given u mine to test it in your car. There is wire somewhere either inside the climate control or outside that draws the power once you turn on the AC button.

Spartan536

Tanin does have a warranty, I can send it out to them under warranty.

AlaskanLS

I am saying don't rely on that climate control the one you have in your car. The only way to find out if your climate control is working flawless is, buy another climate control from a seller who accepts returns on eBay. Even if you spend 100 dollars on separate climate control and once you make sure that yours is fine. You can return the purchased one to eBay seller for full refund. My point is I want to try a different climate in your car to make sure if the problem goes away, if the problem remain, it would mean your original climate is fine. People who rebuild these climate control they don't test it in LS400 cars. They just test with a battery to make sure that it's display turns on and it's button lights are working.

Spartan536

I could try a salvage unit.... I will see what I can come up with.

AlaskanLS

My problem got solved after replacing IACV, rear catalytic converter, distributor caps and ignition rotors. But misfire was caused by the bad ignition coil wire that was the actual culprit. Car runs smooth but replacing rear catalytic converter with a universal one made the exhaust a little bit loader.

TaninAuto

Hi, Tanin Auto Electronix here. Please give us a call today to discuss the issues. We do have warranties and also want to make sure our customers are 100% satisfied with all repairs.

We are open from 9-5 Central time, Monday through Friday. We will be closed on Labor Day.

Spartan536

I spoke with a representative from Tanin, once again solid customer service, always happy to help, my options through them are if the unit is indeed defective, that my cost for repair would go towards a replacement, which is appreciated as I would be getting an entirely rebuilt unit.

However before doing that and heeding the cautionary words on the forums and from Tanin, I will replace my A/C switches and relays just to be sure, they are OEM from 25 years ago so it's quite possible that they would be likely to fail intermittently, hell I just had my ECU rebuilt due to capacitor failure.

I will be replacing the following...

A/C - Radio Fuse: ALREADY COMPLETED

A/C Compressor Relay - (Just to be on the safe side, it's dirt cheap)

A/C Condenser Fan Motor Relay - (Just to be on the safe side, again dirt cheap)

A/C System Relay - (Probable cause of intermittent failure, again dirt cheap)

Radiator Fan Relay - (Still OEM, going to replace just for maintenance).


I have gone over the A/C system diagrams for my 1992 Lexus LS400 (thanks interwebz) and regarding the electronics, while the wires COULD have a short and even the connectors, it's still unlikely. I am an IT hardware professional and even computer connectors that are 20+ years old usually work, it's usually an interconnect or PCB that fails before a pin (unless damaged physically) or wire does, they carry considerably less voltage than Spark Plug Wires, and high voltages take a toll on wires over time.

The relays however, well they do have a higher tendency to fail based on how they are built to operate, everything I have read up on relays from mechanics points me to it being the likely culprit, and it never hurts to replace 20+ year old relays, any mechanic worth their salt will likely tell you to do that for maintenance, it's cheap and easy to do anyway.