Climate control unit/heater blower issues
 

None of the buttons on the climate control unit work. Checked and cleaned all the fuses, they all look good. Next, pulled the passenger floor panel and disconnected the power cable to the heater blower motor. Ran two leads from a 12 volt battery pack to the male plugs on the blower motor, motor turned on and ran (thank goodness!). Next, connected a working test light to the female plug for the heater blower motor and turned the ignition on and then turned on the defrost. The test light did not light, so I'm thinking the problem is the climate control unit. This is on the 1984 300DT, BTW. Other than the climate control unit, are there any other possibilities?

There may be other potential causes, but those symptoms sound like a CCU (I'm on my third unit).

On average how long are they lasting for you? I"m thinking of attempting repair (resolder) on the CCU before ordering a new one.

Hard to say, mine was unreliable when I bought the car in 2001 so I had a shop replace it with one of unknown origin (it may have been used). About 5 years later it acted up again and I bought a reman unit from GDL. That one is still working fine and I believe they will fix/replace it if it fails. Be aware that GDL will not accept a core if it's been worked on.

I just remembered one more thing to check; try wiggling the key. I once had an issue where a worn ignition switch was causing the entire climate control system to not work, but if I wiggled the key it would sometimes turn on. Everything else seemed to be working fine; maybe there is a separate power supply from the ignition switch? Anyway, replacing the ignition switch (electrical part) fixed it.

thanks, I am going to check it out.

I would also give Peter at GDL a call. As I recall, they were willing to test your CCU before selling you a reman if you sent it in first.

Peter's a great guy. You'll get to know him if your CCU or your cruise control acts up. Give him a call, before you try to repair it yourself.

You want to fix it? Read my recent post on climate control actuators. You can "fix" your vents to get the air you want. Send me a PM if you want the details.

But, either your CCU is bad, or your main vacuum line to the CCU is disconnected. Or even another issue. Like someone else already said, it is hard to tell.

thanks for all the suggestions, I happen to have a spare electrical switch on hand so I'm going to try replacing that first. If, no joy, then onto the CCU.

Is it possible to change out the ignition switch without removing the steering lock? If so, what might be the best way to perform an ignition switch swap? thanks!

I think so, but it's tight. I think the key needs to be in #1 position to remove the electrical connector. It's probably easier to just remove the connector and plug in the new switch to test it. Either that or remove the CCU and see if it's getting any power.

CCU
 

Yeah - Pete just redid mine and it's working perfectly for the first time in 14 years...

There are 3 screws that hold the ignition to the steering lock assembly. they face to the rear. if you can remove the screws w/o removing the assy, you Da man.

I have replaced 2 steering lock assy`s. not that big a deal. trying to remove the screws while still installed, will be a bigger job.
the screws are inside the cup area.

http://img.eautopartscatalog.com/liv...1605516VAL.JPG

Charlie

I managed to locate the old steering lock complete with ignition switch and tumbler. This original set up was working correctly prior to replacement (other than the tumbler was sticking). I'm thinking of taking the easy route by connecting the electrical connector to the original ignition switch/steering lock/tumbler with the key in the "on" position without installing the unit in the car (just hold it over the dash panel while I perform the test). I'll then turn on the climate control to see if the fan blows. Hopefully this will confirm whether the problem is a bad ignition switch or not.

question: Shoud I connect the vacuum lines to the steering lock before performing testing the CCU?