[V8] '94 V8 Heater/AC Diagnosis

Joe Fox 2-foxes at comcast.net
Fri Dec 21 08:57:00 PST 2007

Hi Everyone!

Still have problems w/heater controls on my '94 V8:  Most air comes from
dash vents, very little from defrost or footwell outlets.  Fan speeds up
when defrost is selected but vents don't change.  Air recirc. works, closing
the flap outside and flaps move to different positions when changing from
heat to AC.

I removed/replaced the heater box (new heater core) but didn't disturb the
flap positions; wife says it didn't work properly before this.

The control head on the '94 is completely different from the '90 V8; anyone
know if this unit provides self-diagnosis as the older one did?

Checked Family Album, didn't notice any differences in drawings comparing
'90 w/ '94 heating/AC systems.  Didn't see any vacuum servos (ref. 1990
Repair Manual drawing, p. 87-270 items B & C) nor are there any vacuum hoses
running under the heater box as shown in an archives photo.  I see vacuum
controlling only the heater valve and fresh air recirculation flap.  Don't
know if the '94 has vac. hose connector etc. like shown in the Manual
drawing for the '90.

Anyone have a 1994 Repair Manual?

Joe Fox

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