Climate control problems? Read This!

[sly]

The Lincoln would blow weak to the panel and defrost vents before I fixed the vacuum feed line. Still does to a degree because the seals are shot due to being 32 years old, but it blows like a hurricane now and vacuum is STRONG on the main feed line. That may well be your issue if you felt no real vacuum at the black line when you pulled the harness.

[sinistral]

so where's the likely culprit location for the feed line leak?

The Lincoln would blow weak to the panel and defrost vents before I fixed the vacuum feed line. Still does to a degree because the seals are shot due to being 32 years old, but it blows like a hurricane now and vacuum is STRONG on the main feed line. That may well be your issue if you felt no real vacuum at the black line when you pulled the harness.

[sly]

leak? no... probably the feed line has a kink in it. Either way, it's located between the T that you can see under the dash that goes to the controls and the blend door. Those lines very rarely ever gain holes. The problem is that you really cant get to it without removing most of the dash... so just running a new and cutting that one out of the loop fixed the problem (at least for me). It's a bit of a pain in the ass to do though as everything behind the dash is rather cramped, but you don't need to remove anything if you go around by the driver side end of the firewall. Just routing the line takes a minute or 15.

I'd put a gauge on the black line on the main vacuum harness you can reach with the car running and see if you're even getting vacuum first. If not, go to the check valve on the firewall and pull the line that goes straight to the firewall from it (the other one goes to the vacuum reservoir on the driver inner fender) and see if the check valve is sucking air at that point (should be). then check if you can pull a vacuum on the line you pulled off (if you left the harness disconnected you shouldn't be able to - I was able to pull a vacuum, so my line was collapsed/kinked somewhere).

[mitymerc]

If this epic thread is not a sticky it needs to be one....

[TecNickal]

I was having trouble with the automatic climate control in my 89 colony Park. After pulling the vacuum line off the large diaphragm behind the glove box, I learned that I do in fact have hot heat. I was driving to work and noticed that it really wasn't getting all that warm in the wagon during the last few cold mornings.

I do in fact believe that I have a bad interior temperature sensor. I saw gadgets post about the part number from the box but unfortunately I cannot find it anywhere. So I guess during the winter I'm going to have to leave the vacuum line disconnected to have heat but I'd love to have the automatic function working again someday.

Anyways thanks for the excellent write up gadget that was very helpful!

[gadget73]

yea I think they may have gone obsolete. Annoyingly I suspect the fix is going to end up being converting it to a cable drive system.

[sly]

yea I think they may have gone obsolete. Annoyingly I suspect the fix is going to end up being converting it to a cable drive system.

I do believe this will end up being the case. I couldn't find any either. Sourcing the manual system cable may prove difficult though.

[gadget73]

non-ATC cars would yield one, of course they're just as old. At the end of the day its just a wire control cable, one could probably be adapted from a lawn mower or something if it really came to that.

There is also the grossly over-complex method involving something like an Arduino, inputs from a couple of potentiometers set up as position sensors for the blend door and the slider, a thermistor to sense cabin air temperature, and output to a vacuum solenoid that can do PWM to move the blend door around.

[Brown_Muscle]

There must be an alternative part, either ford or otherwise that could be made to work. I'll try more searching later, i think a junkyard search would be most fruitful for trying different things, however I have neither the time or will. I was thinking of an inline vacuum valve you could manually control to activate heat/no heat, crude, but it would be better than manually disconnecting it behind the glove compartment. I may end up doing this as it gets colder just so i have a way to switch it to heat since my ATC sensor is kaput. There are so many sites with the part still up, and pictures of it, its frustrating. I may have to just wait until a NOS one appears on ebay.

[His Royal Ghostliness]

Use a solenoid from the AIR emissions system. Unlike the EVR one those are constant-duty solenoids, and they are self-venting as well - I run one to manually close my recirculating air door for better heat in the winter and also to keep foul smells out while driving thru swamplands and such.

[gadget73]

that would give you hot or cold, no in between. I've considered making it complicated by connecting the temperature selector to a pot, adding something like an arduino to accept input from a pot, a thermistor for cabin temperature monitoring, and output pulse width modulated signals to something like the EVR to drive the blend door. Either that or a linear actuator with a position sensor for feedback. Then I kind of thought about it, decided I don't actually feel like learning to program a stupid computer just to make the door go from hot to cold.

[Brown_Muscle]

A neat idea, but a lot of work. Hot, or cold, is better than just cold, for now. I assume this is a rare option, since there arent a lot of complaints about lack of heat in peoples cars in the past few years.

I'm currently looking at small, inexpensive vacuum regulators, with a knob that could adjust how much vacuum would go to the actuator, however I can't immediately find one that would work, i'll keep looking

[His Royal Ghostliness]

Not a rare option at all, I think all TownCars came with it, higher-trim Grand Marquis cars too in large numbers. Not sure on Crown Vics. But yeah, pretty common issue you have, to the point that IIRC LincolnsOnline had an article about it way way back.

[Brown_Muscle]

In that case I'm surprised no one has come up an easy conversion to cable, or writeup on the subject.

[gadget73]

As long as the part was available I suspect there was little motivation to do it. Now that the part is NLA its a little bit different.