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For the past couple of weeks I've felt like my heat isn't working as it had before. The symptoms are that when the climate control is set to 75° it used to warm up the cabin pretty quick and then the climate control would adjust. Now if I want hot air it seems I need to crank the temp up to 85°, then I can reset it once it hits that temp. At first when I thought the heat had stopped functioning I replaced the engine thermostat which was probably ready to be replaced anyway, and cheap and easy enough to handle.

My guesses now include interior thermostat? The gate that adjusts the cold/warm airflow over the heater core? The heater core itself (though when I crank it up to higher heat warm air does come from the vents so I think the core is fine). Anyone know where the interior thermostat is located and how it can be accessed? Any ideas on what else it may be or what is common to the 92-97 with these symptoms?

Whether you removed the accumulator recently?

atom wrote:Whether you removed the accumulator recently?

I don't think that would affect the heat, would it? I also wouldn't know where to find it. Will that be under the hood, behind the dash? Would that cause the heat to feel less effective? I'll know more about this once weather warms up and I can test the whole system.

Check the coolant level.

Funny you should mention that. I added coolant after the thermo on the engine and noticed when I was under the hood today that it appeared low again. hmmm. I'll be keeping my eye on that, good suggestion MM.

OK, Checked coolant level and that seems OK. I'm having a hard time with the strange weather (icy mornings, cool wet afternoon, don't know how to dress etc.) determining if this is more in the car or my head BUT I recall that in February when it was icy outside I set the thermo to 75 degrees and the car was warm and cozy within a few minutes of starting up. Now I seem to be pushing the temp up to 81 and 82 which "should be" too warm considering how I'm dressed. I'm leaning again toward the problem being the thermostat or perhaps some aspect of the control unit. Is the cabin temperature sensor in the control unit or someplace else, maybe behind the dash?

Nobody has any ideas on this?

My guess here is that the thermostat is behind the upper dashboard on the right side behind those open horizontal slots right next to the cigar lighter. My next guess is that a few phillips heads are all I need to release to access that. (after popping off the main dashboard cover panel which is something I already handled to access radio components)
- Can anyone confirm if:
1. that is where the interior thermostat is located?
2. If so is it as accessible as I'm hoping?
3. Anybody else suspect that the issue is the dashboard thermostat?
-thanks.

If the dash thermostat was your issue, you'd have a blinking display on the ECC. They're either ok or flat BAD. Not 'weak' or 'off'. Your problem is more likely a mix door or actuator, or a plugged up heat exchanger.

Thank you, first rule of troubleshooting is it's always a matter of elimination either by easiest things to test or least costly. So - good to know it can't be the thermo (still curious to know if I have the location correct) The only other symptom I note is that I'm feeling cold air from the column around the shifter. To my super-noob senses that suggests maybe mix door dumping mixed air into the column? Any method to troubleshoot and eliminate other things it isn't?

The interior thermostat is located behind the slotted part of the trim next to the cigarette lighter. The last time i had the dash trim out i cleaned it with a q-tip. It was very dusty in there, maybe this helps.
-James

edit- very accessible, just need to remove a couple of philips screws.

Well, we blew out the heater core today and the situation is unchanged. (heat is still lukewarm) We could see that the pressure water and air went through the core (exchanger?) and there are no apparent leaks so I guess the next tests will be the mix door and actuator. Unfortunately I'll be out of the area for two weeks and by the time return to PA the heat will be in the air. At least I might have the AC figured out by then (but that's a whole 'nother post. I will follow up to include a resolution once I know what it is and perhaps how the initial evidence ay have suggested it. Thanks all, be back soon.