Interior taking a long time to heat up.

[Tman Sr.]

I have searched previous threads and archives but couldn't find any thing directly related to my problem. My apologizes if I've missed it. No that it's goten cold outside i'd like to get this sorted out because the weather is only going to get colder before it gets warmer.The HVAC controls seem to work fine however I just feel that the air comming out of the vents (any position) is just luke warm never HOT. I recently (last summer) replaced the fan motor it was blowing fusing on high. Actually the new (used from Mike goody) motor does the same thing but only on High and when the air conditioning is running, when heating it can run at High all day with no problems.Any help would be apreciated.Thanks'95 Q45t stock.

[Q45tech]

Measure the air temperature from lower heater vents usually 122F [on low speed] after the engine is warmed to temp [174F] which may take 10-15 minutes in really cold conditions.

Impossible to diagnose without accurate temperature data vs time from crank in 15 second intervals!!!!!!!!!!

Usual problem is failure to frequently replace thermostat every few years [say every 4 years or 60k]. THIS SIMPLE STEP usually fixes 90% of them but our experiences is limited to +10F in winter.

Dirty evap or heater core can restrict air flow putting strain on fan motor thus wearing it out faster. When excessive backpressure occur the fan slows down and draws excessive current overheating speed regulator or blowing HVAC fuse.................the fact that it blows on High AC vs High Heat tells you evap is more restrictive than heater core.

Unfortunately the only time most evaps or heater cores get clean are when they fail and get replaced.......................most are barely functioning for years before failure.

[tkd_q45]

Could also be part of the HVAC that mixes warm and cold air. I have that exact problem - the motor that moves the door that mixes the air is no longer working.

Q45 Tech - are 91-94 HVAC systems the same? I ask because I only have a 91 Service manual (and now drive a 94, yes I know I need to get the proper service manual!).

[elwesso]

Tom, use the 94 FSM in PDF from NICO. http://www.nicoclub.com/FSM

The HVAC systems are similar but not the same.. We have a writeup how to fix the mix door (its not the motor, but rather the plastic rod that goes from the motor to do the door).

[ScottJackson]

I agree that if you haven't replaced the thermostate lately, do it first. Not a tough job. The thermostat has a rubber ring that likes to deteriorate and let coolant pass by when it should be completely closed. That prevents warm up in cold weather.

[Meaux]

I can't find the write-up on the door repair...

[Q45denver]

I think this is it:

zer...age=2

[goody90q45]

I recently (last summer) replaced the fan motor it was blowing fusing on high. Actually the new (used from Mike goody) motor does the same thing but only on High and when the air conditioning is running, when heating it can run at High all day with no problems.

It sounds like you have more than one problem going with your Heat/AC system. Is your blower only running on high and can't be turned down to slower sppeds, or off? If so, there's nothing wrong with your blower motor (either of them) but it's the fan control amplifier mounted in the airbox behind the glove compartment. The blades on the motor you bought from me were cleaned up so it won't draw as many amps to do its job. Cleaned blower motor blades and cleaning the face of the condenser in the airbox will extend the life of the next fan control amp that you're going to need to buy. They're about $60 new (plus shipping) from IOS (Joe).