1999 Grand Cherokee Climate Control

Hi everyone,

I'm looking for some help and advice.

I went to the dealer for a climate control problem, it was not heating in the driver side, they had it check and replaced the climate control module. It worked fine for a few month, but now the passenger side heater is not working, they think that there is an objet or something blocking the A/C-Heater system and for that they have to remove the entire unit from the jeep($$$$).

The problem look exacly the same as before but on the passenger side. It getting cool here and my girlfriend it complainning about it a LOT.

Here's how it started, I was stop at a red lite when suddenly it start doing; vroorrrrriiitttt pouf!!!! then no more heater.

The climate control module give an error code "56" that means "right tempurature door travel too large".

I think that the problem seam more like a defective check valve(don't know where it is) or a broken hose(don't know if I should buy a 100$ vacuum pump for 1 use only).

Thank you for your concern. Any thougth is apreciated.

Reply to
Minh-Thuan TRAN
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Approximately 10/27/03 21:58, Minh-Thuan TRAN uttered for posterity:

The doors and such on the Grand are not moved by hoses or vacuum. Everything is moved by servo motors controlled by the automatic temperature controller. All of the positioners and the blower also have feedback that checks their current position against what it should be.

If you get the Factory Service Manual from techauthority, it has a pretty good set of diagnostics where you can test all of the inputs, set all of the outputs [meaning move all of the internal doors and baffles] and check their status. The procedure is pretty lengthy, and dunno if it is the same for the 1999, but you could look for heater control diags on google newsgroups.

Reply to
Lon Stowell

Thank's Lon Stowell,

The link you gave lead me to a new diagnostics I'll take a look soon, from what I read; there is a trap for ventilation allowing the Climate Control system to mix fresh air from outside to the heater, and that trap is probable stuck open.

Thank's again I'll give more info soon.

Reply to
Minh-Thuan TRAN

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