Electric Problem With Climate Control Unit (sc 400

[kevinph99]

Hi guys

My car is 1994 Lexus SC 400. I didn’t know what wrong with my Climate control Unit but there is no information on the panel nor does anything change when pressing on/off buttons. Beside that, The hour and minute buttons on the dash do not change the clock in the dash nor is the temperature displayed when selecting that option. Three months ago the heater didn’t work and now look like whole system shut down. IF anyone who know much about the Lexus, please help me to deal with this problem. I would appreciate the help.

[AWJ]

Sounds like a bad chassis ground again. Start with your battery. Have it tested. Then test the alternator. Make sure all connections are clean. Then check all fuses. I can assist with the location of schematics if the faulty cause is located.

[jzz30]

is the whole system out or is it just the controls? i had to change a fan controller unit cuz it was stuck on high

[Sc400 Tuner]

I have the EXACT same problem! My climate control just went dead, the backlight is still on, but none of the controls work, nor is any info displayed. I ordered a new climate control unit today (list $500!! Ouch!!) I thought the clock thing was just a weird coincidence that it went out too. The time is displayed, but you can’t change the time. Going to suck if that isn’t the problem, a bad ground DOES sound like what it might be, because my built in radar detector has been making some never before heard beep patterns as well. Let me know what happens, and ill do the same, good luck!

[UCF3]

It sounds more like a sensor has gone bad. I was thinking about the power, but SC400 Tuner mentioned the backlight was on. Since they share the same cable, I'm thinking it's either a sensor that needs to be replaced, or like AWJ mentioned the climate control sensor or wire isn't getting power.

kevinph99, could you give us some more details like what's working, and what isn't? Thanks

[Sc400 Tuner]

I just went and quadruple checked my fuses, none are bad. I also whipped up myself a nice little ground cable going from negative battery terminal, to engine block, to chassis. No dice there either. My climate control unit should be here Wednesday morning, so I guess im going to put my faith in that, unless you guys come up with anything different. Thanks for the help.

[AWJ]

Hey, you're in Lexington? I'm in Maysville, KY. I'm going to be doing some work on the car this weekend. Let me know if you need any help.

Good luck.

[Sc400 Tuner]

Well.... It WASNT the climate control unit. So I guess I just spent $500 to fix that dead bulb I had in there. Looks like im off to visit my freindly Lexus technition. Ill save you the time and money, kevinph99, and let you know what the problem was.

EDIT: YES!!! Spoke too soon, I forgot to plug the Volume/AC Control knobs back in. Once I did that everything worked fine, including the clock!! :)

[kevinph99]

Sc400 Tuner

Can you tell me where I can purchase this Part. I have asked the Lexus dealer but they quote me over $600 and need specail order. If you guy know somewhere is cheaper please let me know..If I buy used one Which year will fix with my car (94 SC 400).

Thanks,

[Sc400 Tuner]

For my 93 Sc400, it was part #55902-24010, and I too had to special order it. I was quoted $500, but luckily for me I have a freind who has a Toyota parts account through their business, so I got it for a little less than that. Maybe you can find someone with a parts account, that could purchase the part for you with their discount. OR, the guy at the parts counter mentioned to me that there is a guy out of California who refurbishes them for $300, with a $50 core charge. Unfortunately though this guy only deals with dealerships. Possibly you could mention that at the dealership and they might know of the guy. Good luck.

[alicias]

I had the same problem. Dead LCD, no heat, no A/C, no indicators. Nothing.

I took it to the dealer and prepared for the worst. Supposedly a wire was knocked loose when I had my head and amplifier replaced. The diagnostics took awhile and that's what cost the most.

The good part was that I didn't need a new LCD or climate control unit which would be really expensive. Nowe all I need to do is replace one -- actually I'll probably do all 3 -- bulbs.

I have the Lexus Part number. Does anyone have the Toyota part number? There are more Toyota dealers than there are Lexus dealers.

[UCF3]

You could probably use the Lexus Part number at Toyota. Have you tried radio Shack? Some bulbs might be available there.

[jbarhorst2]

Are you absolutely sure that your cigarette lighter fuse is good??

Do you have power to your cigarette lighter?? When that fuse blows, the climate control does not function.

Tom

[UCF3]

that's actually a good point as well. Alicia, you might want to check that out as well.