I have a 99 Grand Caravan Sport w/ the 3.8L V6. Whenever I turn on the heat I always get only cold air on the pass vents. the only time I get heat from that side is when I slide the pass side to full heat. As soon as I slide it 1 notch off of full heat it turns cold again. Any recommendations on what's wrong? Thanks

Any lights on controls flashing?
Battery been unhooked or changed or anything done to computers and heater system?
You may need to recalibrate the heater/air cond control unit and check for codes.
Look in owners manual and see if it tells you how to recalibrate it. If not post back.
MT-2500

Any lights on controls flashing?
Battery been unhooked or changed or anything done to computers and heater system?
You may need to recalibrate the heater/air cond control unit and check for codes.
Look in owners manual and see if it tells you how to recalibrate it. If not post back.
MT-2500

No lights on controls are flashing. Battery was changed 2 months ago. Other than that car is stock.
I bought the van used back in August so there was no need for heat until it got colder. And colder it's gotten so that's when I found out the pass side is cold.
Also no owners manual so don't know how to recalibrate it.

Try this link for a pdf on calbriation.
If any codes come up post back.
Let us know how it goes.
http://members.troublecodes.net/crunch/Calbration.pdf
Good luck
Mt-2500

Try this link for a pdf on calbriation.
If any codes come up post back.
Let us know how it goes.
http://members.troublecodes.net/crunch/Calbration.pdf
Good luck
Mt-2500

According to the file if none of the lights flash the system has passed diagnostics test and calibration is not needed.

That is what it says but if it has a problem I always run the calbration first. It may show up something when you run it.
MT-2500

Did the test and in the end the rear wiper and intermittent leds alternately flashed a few times and then all the leds turned off? Not sure what that means.

It means you have codes stored or have a problem.
You need to retrieve codes.
When time permits I will try to post something on retrieving codes.
MT-2500

Here is what you need to do to get codes.
http://members.troublecodes.net/crunch/99coderet.pdf
Post back the code no you get. Also at what level.
Mt-2500

Here is the code list.
http://members.troublecodes.net/crunch/99code.pdf
If you have a level one code 9 dig deep and find 5 big ones before you head for the cry/dodge dealer.
They are proud of them 500$ bracket .
Been and done that.
post back your codes.
MT-2500

I have this same problem... I had the four leds flashing indicating a failed calibration/diagnostic and cool down tests and no heat coming out the vents. So, I ran this test and could feel heat coming out of the system during the test.. the van passed the test and I STILL cannot get heat out of the vents. Any ideas?

oh, by the way I have a 97 grand voyager 3.3 with 116K miles.

Thanks,
Laura

Ihomen
If you ran the calbration test and code test and nothing came up.
Go the each level test from level 1 up to level 5.
Mt-2500

Ran the tests twice this afternoon and noticed that the leds flashing alternately happened during the diagnostic tests. When the tests were complete all the leds turned off.
During the entire test only the wiper and interm. wiper leds flashed. Once done all leds turned off and system went back to normal.
So any recommendations?

By the way, the problem that I have is that it's either cold or hot, no warm. That's probably why it passed the diagnostics test.

Krushmoto
I am running out of info on it.
Go threw level 2-3-4-5 test.
Here is a link to trouble shooting on mode control.
http://members.troublecodes.net/crunch/99trouble.pdf
If you do not find anything there the next step may be to the dealer or someone that has the dodge scan tool DRB11 or later.
Good Luck
MT-2500

Did the test several times and according to the link you sent me, the wiper led should blink when the test is complete but instead it seems to cycle out of the diagnostics/calibration test as soon as it's done. Is something wrong?
Once I hit the defog button while the calibration/diagnostics test was conducting and all the leds lit up and was "stuck" there until I redid the test then it reset.
Any ideas what's going on?