No Heater no A/C

8 years old, how's your 12 v

 

have you tried manual?

 

The heater just works off the internal heat of the engine. So if it's blowing, it should be transferring heat.

Have you tried raising the temp. with the button to the left? (up/down) Just asking. It works by circulating fluid threw the engine. If the engines hot, heat reaches easily to passenger compartment with the help of the blower

I wouldn't go to the dealer just yet. Think you'll get it. A.C. is a bit more complicated but heat is, if the blower's working, should be an easy fix.

 

might be a bad thermostat.

 

Just wondering Bisco. Wouldn't the car be over heating if it was a bad thermostat?

Or is there a second, besides the ICE one?

 

How’s the engine coolant level?

Have you tried to feel the reservoir or hoses after the Prius is run for a bit?

 

if it were stuck closed, it would over heat. if it is stuck open, it won't warm up. i think the failsafe is open, so it won't overheat.
also, the coolant valve could be bad.

 

OIC, thanks.

 

Any trouble codes from the heater? (Hold down auto+recirc while putting the car ON; look for two-digit codes where the set temperature usually shows.)

There might not be any, but there's no point in not checking when it's so easy.

-Chap

 

How about switching to power drive mode?

 

The thermostat is located by the water pump down low on the passenger side. We’re the hoses warm?

 

I've had a thermostat failing, in such a manner that the engine was cooling too well. It's supposed to stay closed until the engine's warmed, but if the gasket's frayed, and/or the mechanism is allowing it to open too soon (and close too late), and you're doing something like freeway driving, the coolant will be flowing freely to the radiator, and cooling too efficiently.

Back in the day with the 1990 Accord in question, there was this quaint old-school gauge in the dash that showed your coolant temp. (If this sounds like a rant, it's because it is.) Anyway, commuting to work up the valley, I'd notice, as I was coming off the freeway, the coolant gauge needle was right down at the cold end, not good.

 

You can check the coolant temperature by grabbing some hoses after the engine has warmed up some, or by using any OBD-II reader to watch the coolant temperature.

If the coolant gets hot, there's really only one other plausible culprit. The heater's air discharge temperature is controlled by an "air mix" door that moves to control how much of the air goes through the heater core, picking up the heat from the coolant, and how much of the air goes around it. I would try to get a good view of the servo linkage that moves that door (up under the dash) to see if it moves, and covers its full range of motion. You should be able to see it move all the way to the cold end (directing all air around the core, not through it) if you just set the temperature to LO, and then if you change the setting to (anything several degrees higher than the surroundings), it should swing in the heating direction.

-Chap