tony597fitter

my 97 interior is COLD!! Its -20f here in chicago at 4:00am, and I only have heat on the recir. setting. That would be fine but my windows fog/ice and my feet freeze. I have searched and I think I have checked everything. I have checked vacuum at the actuators and I have 30 in./hg. I have pulled the temp selector and disconnected the temp control cable and the blend door is functioning right. The only thing I can think of is the recirc. door actuator. How does it work? I only get vacuum at the actuator hose fitting when I put the selector to the recir. setting. Am I supposed to have vacuum at other settings, to mix the inside and outside air?

TRCM

sounds like the problem I had on my mercury s/w. it was the blend door actuator. it failed in a mid position, so I had hot & cold air mixed all the time.

replaced it (royal gold covered silver tipped PITA), and it's all fine now. I managed to replace it without removing the windshield, which is how it's supposed to be done.

I have no clue how hard it would be on a truck

54larry

My '96 only gets warm when you put it on recirc. I was up in Northern PA this last weekend and was reduced to buying a little cigarette-lighter plug-in heater at Advance auto that will about halfway keep the windshield clear.

My defrost and other settings are warmer than the outside air, but way colder than my hands.

I am guessing from the threads I have read on here that the blend door is the culprit, but I tried the "cardboard in front of the radiator" trick, and not only did it not help the heater/ defroster problem much, the truck itself did not seem to operate much warmer even though virtually all of the radiator is covered. That REALLY has me stumped.

tony597fitter

I have done everything to. Cardboard in radiator, removed fan, checked vacuum, checked actuators, checked temp control cable which I think is hooked up to the blend door?
I removed the temp cable from the selector and moved it by hand and it slid easily and I could hear the blend door opening and closing.
I drove it this way this morning and afternoon 75 miles each way and froze my a$$ off. Kept switching between recirc. and defrost to de-ice my windows.
I guess I am going to flush the heater core this weekend and install a ne thermostat, hopefully this helps, because I dont know what else to do.

ANY MORE HELP OR IDEAS WOULD BE HIGHLY APPRECIATED!!!!!!!!!!
I have been searching and searching, and I also have a factory service manual, and i still am stumped.

GAmes

You didn't say if your temp gauge comes up to normal. If not you need a new thermostat.

Earthmover627

I had to change my thermostat and my antifreeze and now it gets hot in my 98

tony597fitter

Thermostat when on the recirc. setting comes up to 190 then drops to about 180 and stays there. And the heat gets hot in the cab,(and foggy).
On any other setting it gets to 190 then drops to 140 or lower and fluctuates. From what I have read this is normal, right? On any of these settings the heat only gets luke warm at best.

54larry

by swapping out the T-stat. No help.

tony597fitter

Yeah, I thought changing the thermostat might not do much. But since I just bought the truck I thought it couldnt hurt.

Now could someone tell me how the heating system under the dash works? ie:vacuum actuators and what they do, blend doors, recirc. doors, etc.
Thanks

SoTexRattler

Food for thought...

IF, you have a plug of some sort in the hot water lines going to/from your heater core, you'll never get warm. Try feeling the temperature of the waterline going to the heater core and compare it with the return line to see if you are actually getting any decent hot water flow through the core. If the heater and fan is on high and the return line is cold, you've got a hot water flow problem and not a blend door problem.

You know,...Come to think of it,... I believe there IS a "restricting orifice" located somewhere in the hot water lines to-or-from the heater core. If it got further plugged with a small piece of debris, it would severely cut your heat down .
I believe I remember reading about it's existance when it came up in someone's thread about a strange "gurgling" sound coming from the dash area. I even believe there was a (1996?) TSB on the gurgling complaint and there was an associated diagram that indicated the location of the orifice.

Try searching the TSB's and see if the diagram is in there. It'll give you a little heads-up when under the hood.

Tonight I'll take a look in my '97 FSM and see if it is detailed in that manual.

Good luck!

K.

tony597fitter

Thanks rattler.
I did check my supply and return lines after a 75 mile run in -20 degree weather. The supply line was hot and the return line was probably 15-20 degrees cooler. I was going to do a flush this weekend (brother has a 6 car garage with heat that FITS my truck, unlike my $300,000 custom house where my truck is 5" to long to do my own work in my own heated garage). Keep telling the wife that I have to build another bay garage to go along with the new truck.LOL!

SoTexRattler

I went to do some searching in the TSBs but didn't find it. I may have to search through DTR on "gurgling noise" to find the reference to it.

Good luck on the heat! No fun driving cold!

K.

tony597fitter

Hey rattler, let me know what you come up with PLEASE. Just shoot me a pm.
Thanks,
Tony

SoTexRattler

FOUND IT!
http://dodgeram.org/tech/dsl/trouble.../isb_noise.htm

I gotta' scram right now, but I'll look it up in the '97 FSM after I get back home tonight.

K.