98 taurus ac more than heat

[73qcode]

I flushed heater core like others said I should. Put in a new thermostat and replaced the water pump. I get good heat in the vent position and in all heater and defrost positions only when I unplug the ac compressor. With it plugged in, the ac tends to override the heater so much so that the windshield gets frost on the inside of it. Is there a control to shut off the ac when the heater is selected? If not will it ruin the compressor if I left it unplugged for the winter?

[shorod]

Welcome to the forum!

Does your Taurus have the electronic climate control, or the manual controls with the knobs?

If the manual system, the A/C should not be turned on unless A/C or defrost is selected. Once you post which system you have, I'll take a look at the wiring diagrams to see if something jumps out as a good test/check.

-Rod

[73qcode]

My taurus has electric controls. I pulled off the radio plate and it has a lot of wires coming off of the switches. I watched the movement of a door open and close when I change the temp control from hot to cold. When I turn it all the way to hot, I see it move and when it stops I hear a slight thud as though it does close all the way. If this one can't be figured out I'm gonna find which wire going to the compressor plug has voltage on it with my meter and snip it to wire in a switch so I can turn the compressor on and off all winter. Maybe I can save the compressor until spring. My other car is a 73 Mach1 and I won't drive it to work while this car is in being fixed.

[shorod]

Rather than snip the pink wire at the EATC module, you might be better off to tie in to the relay under the hood for the A/C compressor clutch. That would be a bit cleaner to reverse.

As for trying to determine the issue, the EATC has a diagnostic self test mode that you can enable without any special tools. The sequence of buttons to press to enable the self test has been posted before on this forum.

Since it seems people don't tend to use the search function of the forum, I'll leave it as an exercise for you to use the "Search this forum" feature from the Taurus forum main page and search for the appropriate key word. If you have difficulty finding it, let us know.

-Rod

[73qcode]

I used the forum search to find the EATC test by FORD. It does not apply to my 98 taurus because it wanted me to push buttons, all I have is knobs. I'll check for the pink wire in the plug to the compressor for voltage this weekend. If I snip it, shrink tubing will hide what I did later. Thanks for the help!

[shorod]

Okay, so you have the manual controls with the knobs. Based off your comment in post #3, I looked into the wiring for the EATC. The "pink wire" comment may not apply. I'll have to take a look at the wiring diagrams again to see what is applicable for the manual controls.

Yours may be as simple as a faulty selector switch that for whatever reason keeps the A/C activated all the time.

-Rod

[shorod]

Yep, on your '98 with manual A/C controls, it's still the pink wire from the control head that makes the request of the PCM to activate the A/C compressor. The signal from the control head goes through two pressure switches and to the PCM. The PCM then controls the A/C clutch relay in the engine compartment fuse/relay box.

Since your '98 has the discrete A/C clutch relay rather than the previous CCRM, I'd suggest you try swapping the relay with a different or new one and see if that fixes the problem. Maybe the relay is just stuck, in which case cutting the pink wire won't gain you anything but giving something else to fix.

-Rod