Mechanics

IT ALL WORKED, EXCEPT THE HEAT, RAN CALIBRATION NOW, NO HEAT OR AC.

1998 Dodge Caravan • 240,000 miles

I have a 1998 Dodge Caravan. It was fine till I went to turn the heat on. There was no heat at all.

I ran the calibration test and got a code where the Rear Wiper LED flashed once, the intermittent LED flashed 4, 5 or 6 times. Of course the Rear Wiper LED flashes once before the other codes, 1-4, 1-5, 1-6

It seemed to me the code was saying there was a problem with the Evaporator probe (open or shorted).
I replaced the probe twice. Re-ran the calibration test again and got the same results.

I ran the cool down test and it failed. When it failed both the Rear Wiper and Intermittent LED's flashed at the same time.

Prior to all this everything worked, I live in Southern Florida, so don't need the heat often. I just randomly tried it. It used to work. Now none of it works. I need the AC!

The fan works fine, I can hear the blend doors moving during the calibration.

Is there a way to bypass the "codes" and get back to where I was before all this happened?

Ray
Avatar
Rayzor
June 21, 2012.



Was there any issues prior to the calibration?

Roy

ASEMaster6371
Jun 21, 2012.
There was no heat, I did not need heat. I just stumbled on the fact it was not working. Ray

Tiny
Rayzor
Jun 21, 2012.
Were all the lights blinking before you tried the calibration?

Roy

ASEMaster6371
Jun 21, 2012.
Nothing was flashing, I only ran the calibration to get the heat working. This has occurred twice in the 12 years I have owned this van. In the past the calibration fixed it. Today is different.

Ray

Tiny
Rayzor
Jun 21, 2012.
All the flashing that is happening now only started after the calibration.

Tiny
Rayzor
Jun 21, 2012.
Is there a way to kill the calibration codes and get back to where I only had "no heat". I don't really need the heat in Southern Florida.

Tiny
Rayzor
Jun 21, 2012.
The reason for all my questions is background as you now have a failure and I do not think calibration is going to solve it.

Did you do the basics for no heat? Coolant, thermostat, heater core circulation. If all that is good, then we move to the inside for checking the blend door movement. Calibration should take place after the problem is found, repaired and verified.

Basics, basics.

Roy

ASEMaster6371
Jun 21, 2012.
Hi guys. If you mean "no heat" as in it blows cold air, feel the heater hoses. They should be too hot to hold onto for very long. If they are not, suspect a plugged heater core. They can usually be cleared by running water from a garden hose through them.

If you mean "no heat" as in the system turns off, replace the computer. It is the entire bezel around the radio.

If the heater hoses are hot, the temperature blend door actuator could be broken or disconnected. There is a position sensor on it that would not change so that would fail the Actuator Calibration test.

The Cool Down test can be extremely frustrating to get it to pass even when everything is working correctly. My record is 20 attempts before it worked. You might find some useful information at the bottom of this page:

http://randysrepairshop.net/reprogramming-the-chrysler-hvac-computer.html

Caradiodoc
Jun 21, 2012.
I did check the coolant levels, they were fine. Nothing unusual at all, except for no heat.

I ran both the calibration and cool down. Both failed even after I replaced the evaporator probe.

I tried to kill the codes by disconnecting the battery for about 20 minutes. I now know the codes are stored somewhere.

Can I erase the codes?

Tiny
Rayzor
Jun 21, 2012.
Do not disconnect the battery. THAT is why the HVAC Computer has to be recalibrated. It loses its memory.

Caradiodoc
Jun 22, 2012.
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