Akinley

Hi, I have an 87 GT with a strange problem. The indoor blower will work with the key on and engine not running. It won't switch off of defrost and when I start the engine the blower won't run at all. Checked power at the control and it loses power with car running. Any thoughts?

Akinley

Figured out why the fan wouldn't run with engine running. Had to role the key back a little. Must have messed up when I replaced ignition switch.
Still won't switch off defrost though and AC compressor not coming on.

mongolchuck

The stuck on defrost problem is most likely a vacuum issue. Check the lines under the dash and through the firewall. The a.c. comp not cycling could be a bunch of issues. Low fee on, bad pressure switch, blown fuse, bad comp clutch. To start see if you have power to the comp clutch.

dawson1112

The blend doors will default to defrost and heat when the vacuum is too low. Its a built in feature to ensure that you alway are able to defrost the windows in the winter.

Akinley

Good to know. Thank you. I will check out the vacuum lines.