Heater blows cold.......Need Help!

[4dmalamute]

I havent used the heater on my 1993 fzj80 in a long time and the other day when I turned it on.................no heat!! It blows air like normal, just with no heat. This is the same with the rear heater. I have packed up all my books (middle of moving) so I cant research it at the moment. Anyone have any ideas as to where I should start? Oh yes, the temp. on the cruiser is constant, just flushed and replaced Thermastat a few months back.

 

[-Spike-]

I'd start with the heater valve. It's inline on one of the hoses at the back of the engine, right above the valve cover. Check out waht position it's in, then with the ignition on move the temp slider opposite of whatever it was on originally. The arm on the valve should change position. If it doesn't, IIRC it's easy to remove the linkage and open it by hand. If it doesn't move easily by hand, be prepared to replace it. In other words, make sure you don't force it right before you have to drive the truck somewhere, as it may break.

-Spike

 

[4dmalamute]

Thanks for the input Spike. I will check that out this morning. If anyone else has an idea or even a picture (yes pictures are good........takes the guess work out for me ) please post it up. Thanks again and hopefully I can find the problem.

 

[4dmalamute]

So I checked out the valve, and it moves perfectly. I disconnected the hose, and flushed the core. Question though, should the heater core flush even if I slide the control to the cool side? It seems to flush the same no matter if the control is on the cool or heat side.

Does this mean the control valve is faulty? Damn, I am confused. Any ideas

 

[-Spike-]

The control is electric IIRC, so make sure the valve itself is open when you flush it. AFAIK the duct is set up to run through the heater core all the time and temp is controlled by coolant flow, so if coolant is flowing through the core it pretty much has to heat the air going through. Truck at operating temp? Try the rear heater, see if that one works at all.

-Spike

 

[4dmalamute]

The problem is fixed............for now. I flushed the line, even looked to see if the switch was opening and closing when switching from hot to cold....all looks good. I guess something was clogging it??? Anyway, let the beast idle for 20 minutes, turn the hot air on and all is good. I drove it around, the whole time going from hot to cold and all seems good. Thanks for the help spike!!