Rear heater not working! (1 Viewer)

[kup99]

Well, this one is pretty straight forward.. it's starting to get cold, tried the rear heater at the end of last year, and noticed that it wasn't working... needless to say, it's time to fix it!! my question is .. is there anything to fix, or do I just buy a new one? I am assuming I need to remove the center console?

Thanks gang!!

 

[96r50]

The rear heater has it's own 20 amp fuse in the box by the driver's left knee, I'd check that first. After that, what is the problem exactly? Is it not blowing any air (electrical issue) or is it blowing cool air (coolant issue)? It's a pretty simple circuit so it shouldn't be too hard to troubleshoot with some more info.

 

[kup99]

sorry i didn't describe enough... only blowing cool air!! i'll check the fuse right now!!

 

[kup99]

fuse is good!!

 

[Lka1988]

The rear heater will only blow hot air if the front heater is on. IME, at least.

EDIT: The slider has to be in the 'hot' position.

 

[kup99]

i'll try again tomorrow, but I thought i had it on hot last winter... I'll keep you posted!!

 

[kup99]

Front blows hot, rear is freezing!! fan seems to work, but no heat in the rear! any ideas?

 

[chappysfj40]

mine too but only its a 60 so i will be watching this one close.

thanks again

 

[kup99]

anyone want to offer up a suggestion?

 

[96r50]

It sounds like the hot coolant from the engine isn't making it to/through the rear heater core. If the fan works on both speeds, then there are no other electrical connections to diagnose. Has the rear heater ever worked for you? Is it possible that a PO bypassed the rear heater core? I did this to mine, so I have a fully functioning rear heater core assembly if you need one.

The rear heater line branches off from the front heater above the valve cover, runs down the firewall and under the passenger floorboard above the exhaust and into the rear heater core. After flowing through the core, it comes back out and runs up to the firewall where it branches back into the heater return line running along the passenger side of the engine. The rear heater core could be plugged or bypassed with no effect on the rest of the cooling system. It is a parallel circuit, not in series with the rest of the cooling system.

At this point you need to determine if the coolant is making it through the rear heater core. There really is no quick and easy way to do that as far as I can tell. You need to drain the coolant from the engine, disconnect the rear heater from the rest of the system and see if you can flush water or low pressure compressed air through there. If you can't, then the core is plugged (not sure if this has happened to anyone before)

 

[AJP]

well first put the main heater control to high and then reach under PS seat from rear and feel the rear heater - if it is warm/hot....then the blower isn't able to force air through the core. If is is cold then no hot water is getting to the core -- suggesting a) it has been bypassed b) the line(s) has been pinched preventing water flow through the heater core or c) crud is blocking the lines/core.
I have had to replace several of the clamps on the hoses to the rear heater due to rust - presumably not your problem if your vehicle is not leaking coolant.

 

[kup99]

Thanks... I'll look into these things tonight!!

 

[AmukCanuk]

x2 What 96r50 said.

I bypassed the motor coolant loop to the rear heater in mine, and it now operates in exactly the same manner as yours does now.

Good luck.