My '99 GC LTD. HVAC system isn't giving me any heat whatsoever, so I used the diagnostic method of pressing the a/c and recirc. buttons simultaneously, and then turning one of the temp. control dials one click to see if any codes came up. I got the following numbers: 16, 38, and 54. Could anyone possibly tell me what these numbers relate to?
Appreciate any help.

Bob

16= Door not responding - Blend Air Door Actuator Drive Circuit
38=Circuit was shorted-Front Panel Mode Control Input
54 I dont have it is marked reserved, my manual is a 96, 54 mustbe a updated code.

54 is left temperature door travel too large.what usually happens is the blend doors inside the heater case break.then the motor that controls the temperature can keep turning when it should have been stopped by the door reaching the end of its travel.usually you also get a problem where one side will ony blow cold or heat.it doesnt matter where you set the temp.if this is the case you need to take the heater case out of the car to fix it.also code 16 = Right temperature door not responding and 38 = Mode pot was open .for the 16,it could be the actual blend door motor.as for the 38 its a history code so it might not be anything to worry about

Thank you very much for the help. I'll update after I get this fixed. One more question...is the heater core a part within the heater case, or a completely separate component? Thanks again.

Bob

I'm now also getting a code "52", to go along with 16, 38, & 54.
May I ask what 52 means? Thanks so much.

Bob

About codes:
how can you can you see which one you have?
I have 2001 GC Laredo I6.

About codes:
how can you can you see which one you have?
I have 2001 GC Laredo I6.


Your GC Laredo would have to be equipped with the dual zone climate control system to have the HVAC error codes displayed on the digital display. If you have this system, just follow the procedure I mentioned in the first post and the codes will come up (if there is a problem in the HVAC system that the on board diagnostics is capable of detecting). Good luck.

Bob

P.S. Love to know what code 52 means, if anyone has it handy. Thanks.

code 52 is a history code Mode door travel range too large