Heater Controls

c206a · October 17, 2009

my 1999[new style],only blows cool to lukewarm air at the best, this is with the heat control turned fully hot.I know it is not the thermostat because the temp gauge sits in the middle where it has always sat,the top rad hose is hot ,bottom rad hose is lukewarm, the heater,input hose is hot, the return hose is pretty much cold,so it is either a plugged heater core,which i can backflush myself or it is the heat control.If it is the heat control,can someone explain how it works, how to get at it and how to check to see that it's working properly.I assume the dash has to come apart and also access the heater core.Thanks

txab · October 17, 2009

Sounds like a plugged core. Hopefully gently flushing it might open it back up. Be prepared to replace it though. The heater core should have water running through it all the time. No valve to shut it off. There is a blend door that allows air to flow over the core or not to flow.

You do have plenty of water in the system don't you?

c206a · October 17, 2009

Sounds like a plugged core. Hopefully gently flushing it might open it back up. Be prepared to replace it though. The heater core should have water running through it all the time. No valve to shut it off. There is a blend door that allows air to flow over the core or not to flow.

You do have plenty of water in the system don't you?

yes the system is topped up, gonna try backflushing it with a garden hose today or tommorrow,i also found an old post about the actuator and how to change it,doubt thats what it is though.Thanks very much for your help. Gary

REV353 · October 17, 2009

I would put some coolant flush in first, then drive it for a day. Make sure you remove both heater core lines before you flush too, otherwise that same crap will be floating in your system and going right back where it came from.

c206a · October 22, 2009

thanks guys,on sunday i pulled the heater hoses off the core at the firewall, stuck the garden hose on the return line,and a bunch of brown water/crap came out,for about 30 seconds.Put the lines back on, fired it up and presto,instant heat.seriously.Seriously i went from no heat,to roast me out hot.I think i am going to flush the whole system,and i should be good to go for the winter.Thanks guys for your help.