99 Crown Vic check engine light

[rickheel48]

OK, I have replaced 6 of the 8 coils on the car. When I got it back the last time I drove it for a while and the cel came back on. I was leaving a toll booth, got up to speed, and the light started flashing. I lost a bit of power. Another thing I noticed was my air conditioning air was warm. I got home and checked the AC compressor and the lines were ice cold. No cold air coming into the cabin though. Any ideas? Thanks in advance for any and all help. Rick

[ABE]

For the CEL you need to have the codes read, I think Autozone does that free of charge.

For your A/C there is a cycling switch on the drier which I believe is mounted near the firewall on your car, and can fail. Test it by removing the two connections and bridging them to see if the A/C works. If it does then replace the switch.

The HVAC uses vacuum motors to control the 3 doors in the system. If engine vacuum at the vacuum canister is low then the doors will not be set correctly and cause a problem like you describe.

The engine and HVAC problems could be linked by a vacuum leak, check all the hoses, particularly the PCV hose.

Hope this helps.

[rickheel48]

Well, I went under the hood and found that squirrels had chewed two wires in two, and had chewed up a couple of others.There was a plastic tube going to a connection on the firewall mounted control which was chewed in half too. Fixed that but the AC still is not working.

[ABE]

Originally Posted by rickheel48

Well, I went under the hood and found that squirrels had chewed two wires in two, and had chewed up a couple of others.There was a plastic tube going to a connection on the firewall mounted control which was chewed in half too. Fixed that but the AC still is not working.

Previously we talked about a vacuum problem causing engine performance issue and possibly the HVAC issue. The plastic tube and control unit could be the vacuum reservoir for the HVAC controls which I think is mounted on the firewall. Can you hear the vacuum motors for the HVAC doors, light hiss as they work. Probably easier to hear shortly after stopping engine and listening for the hiss as you change the HVAC from floor to defrost, etc. If you cannot hear the hiss then the vacuum accumulator is not holding a vacuum or the coloured hoses have disconnected from the controls under the dash.

Hope this helps.