Heater and A/C dash control not functioning - erratic engine idle.

[Viper Guy]

Hi! Just got my '81 DeLorean a month ago and find the heat and A/C dash control does not function. There is no A/C clutch engagement, no blower, and no position switching like from heat to A/C to defrost, etc. The fuses look good but that's all I have been able to check. Any ideas? Thanks!

Also, the engine idle is erratic after cold start during warm-up. Once at operating temp, the idle is smooth. I am excited about owning this vehicle but is totally new to me and I have never had any previous DeLorean experience whatsoever.

The car is a 5-speed manual with 34K miles if this helps.

[Jonathan]

Welcome to DeLorean ownership! ...and good luck, may the force be with you, live long and prosper, yada yada :)

Could you post some photos of your car for these issues? Perhaps some images of the engine bay including the A/C compressor as well as the throttle spool area, and firewall area of the ballast resistor and engine cover latch. An image of the front of the HVAC control panel may help, or behind it if you have some of it apart to see what may be going on behind the mode control switch. Add a couple photos of the relay and fuse area behind the passenger seat under the Lotus specialty plywood of the parcel shelf and that should do it.

Your mode control switch giving you heat, vent, A/C, bi-level, etc. could be an easy fix if the vacuum hoses aren't connected properly or the seals need lubing. It's not terribly difficult to gain access to, but let's do that only when we need to. It would explain you not having any selections and might be affecting your idle if the vacuum is the problem. Vacuum leaks in the engine bay can be obvious for some locations and challenging to find for others.

Educate us a bit on your car and we'll help get it figured out.

[NightFlyer]

Jonathan has it all covered! :thumbup:

[mluder]

It's not uncommon to have an erratic idle on cold start. That will happen as the lambda system "warms up." Once the engine is at normal operating temp and the lambda is doing it's thing it should settle in around 750 RPMs give or take 10-15 RPMs.

Now - that's not saying you don't still have a vacuum leak somewhere that's affecting your climate control mode switch which is dependent upon vacuum for operation.


Cheers
Steven

[Domi]

Welcome to the forum ;)

[Viper Guy]

Everyone, thanks for your replies and a special thanks to Tamir for helping me get going on the forum.

I'll be glad to take some pics but the car is stored at a friend's garage about 30 miles away. I am attaching one of the engine but will get more asap and I hope the attchment goes through. I can tell you that a new fuse block was installed within the past year by the previous owner as the old one kinda melted. There was an update done at the time with some wires placed in an empty area of where I think a relay would be if there was one. He gave me the info on that.

I was able to get A/C pressure readings and know there was plenty there to engage the clutch. Since I wasn't able to do that through the control swithch on the dash, I jumped the compressor from the HOT wire in the enginge compartment and learned my compressor is bad. It turned but squealed like a pig after a few revolutions. I ordered a new one from DMC and also learned from them that it is best to stay with R-12 freon. No problem there, my A/C guy can fix me up.

[Viper Guy]

As per other's suggestions, I am attaching photos of my engine compartment and fuse block area. My dash control has no functionality and I am under the impression that all wiring is correct, but.............

Please advise if you see something I need to fix.

Thanks,

Fred

[NightFlyer]

Check fuse 10, should be a yellow 20A.

[Jonathan]

http://dmctalk.org/showthread.php?40...ull=1#post7640

Have a look through the fuse and relay area schematic in this post as well as the other individual diagrams in this thread. You can see the correct fuse colours/ratings for what is intended on being in there (as Nightflyer pointed out).

I suspect you are going to need to access the mode control switch from behind. That being said, here are a couple other easy things to check on your car.

In the engine bay, have a look over and behind the air filter housing and tell us if you see a hole there and whether it is sealed (either from factory or with something random like a golf tee). This item on the DMC website is meant to go in there and plug it:

http://store.delorean.com/p-6399-plug-removeable.aspx

If you click back to the main 1-4-1 Air Induction System page (here: http://store.delorean.com/c-334-1-4-1-air-induction-system.aspx) you can see it shown as item #14. There are actually two number 14's, one is the replacement plug and one was the original.

That hole is how you access the fuel mixture adjustment and if someone has accessed yours in the past (which we'll just leave the way it is for now), you need to keep the hole plugged as vacuum leaks through it if not.

Also on that same 1-4-1 diagram are three of these: http://store.delorean.com/p-6400-plug.aspx

Item #15 and it also plugs a vacuum hole. You can see them in a couple of your photos and all you want to do is make sure they are fairly tight and not missing or obviously loose.

Let us know what you find.