99 grand prix has air conditioning only on blower switch setting #5.

historically it has a leak into the front of the r passenger compartment only with rain. can't duplicate except once in rain and leaks only a small amount down inside the passenger door near the exterior mirror with hosing car (for about a yr). ( 2 dr not 4 door car) (defective seal?)

yesterday noted air conditioning only worked in blower position 5 for air conditioning with engine running. with engine not turning but key in on position all the five fan speeds work and blower seems fine. with engine running and turning the switch from off to 5, a delay of 3-5 seconds occurs before the air blower comes on and seems to provide cold air just fine.

also the running lights go off with the engine running in switch postions 1-4 and are ok if in the off position or if in position # 5. i can hear a relay click in a small box with two sets of wires under the steering column on the driver side when the key is turned to the ignition on position. i need to know if that is the control module or if not, where it's located. is it near the blower on the passenger's side or on driver's side?

is the cause the control module? and where is it? or is it something else.

any links to diagrams pictures of the module location resistor etc would be appreciated as well.

thanks.

Welcome to AF.

Check the cowling seals at the HVAC air intake area passenger side. Also, a cabin air filter helps provides protection against water intrusion.

Based on your symptoms you have the classic signs of an ignition switch going South. You can try the blower motor resistor which is located behind the blower motor against the firewall passenger side but that may not resolve the issue.

Also, just to be sure make sure the battery is good and the alternator is putting out the proper voltage. Check the battery terminals and both positive and negative cable connections.