Heat not hot - already replaced blower

[NancyWeir]

Hope that someone here can help. Vehicle is a 99 Cherokee (stock). I had the whole intermittent heat problem that so many Jeep owners have, and replaced the resistor, now the blower motor. So, my switch now works and I have levels 1 - high, but the heat blows lukewarm at best. Don't know if this is related, but I blew a radiator hose a couple of weeks ago. Since I did not have a blower then (and didn't even try to use the heat as it was still hot out) I can't say if this is when the heat stopped working. My mechanical hubby is currently (as I write this) backflushing the system to see if this helps. :?|

Any ideas?

Thanks,
Nancy

 

[jay79cj7]

If you had your radiator replaced recently, you probably have a big slug of air in your heater core. There's also a blend door in the box to control temperature. It could be stuck, keeping the air from blowing over the heater core. The motor is on the bottom of the box, just to the passenger side of the trans hump. You can tell if its working by turning the temp knob back and forth and see if the motor moves.

 

[Low Ranger]

We had an older (93) sport cherokee with the 4.0 engine, and it had a vacuum controlled bypass valve to divert the hot water from the heater core in the summer. perhaps you've lost the vacuum to it. follow on of the small coolant hoses from the front of the engine towards the firewall and you'll find it.

 

[Dirk]

Could also be a thermostat that is stuck open.

 

[NancyWeir]

Thank you for the responses, I relayed all of your suggestions to the hubby! Yes, I now have heat. This last weekend, my hubby blasted some water through the heater core, and he said, "A big slug of sludge came out." I think the hose blowing caused an air pocket, loss of vacuum, and rust sediment. It was a simple solution, but it took how many months to fix? :?| Just happy to be able to turn the heat DOWN as the snow falls in Michigan.

Next step, electrical problems.

Again, thanks to all on the board. Love my Jeep, but she's got PMS lately.

Nancy