BAC Forum

General Boards => Technical Support => Topic started by: Bill Lampkin on July 21, 2023, 04:40:57 AM

Title: 08 marquis dash hvac schematic
Post by: Bill Lampkin on July 21, 2023, 04:40:57 AM

Anybody have a wiring diagram for 08 marquis? Tried those on coachnet  but no dash h ac diagram there

Title: Re: 08 marquis dash hvac schematic
Post by: Steve Huber on July 23, 2023, 03:49:32 PM

Bill,
What problem are you trying to solve?
Steve

Title: Re: 08 marquis dash hvac schematic
Post by: Bill Lampkin on July 23, 2023, 03:55:58 PM

Friend w/ 08 marquis says his dash heat/ac controls don't work.

Title: Re: 08 marquis dash hvac schematic
Post by: Steve Huber on July 23, 2023, 05:48:53 PM

I think his system still uses a vacuum pump to control the mode switch. If so the vacuum hose from the pump or the pump itself could be bad. If someone was trying to neaten up the wiring under the front cap, they could have inadvertently captured the vacuum hose in a wire bundle tied up with a plastic tie, cutting off the vacuum to the control. The pump should be located on the pass side near the top of the firewall and is easily accessible with the geni slide open. On my 07 the pump is a Ford pump.
Steve

Title: Re: 08 marquis dash hvac schematic
Post by: Bill Lampkin on July 23, 2023, 11:45:14 PM

Thanks steve