08 marquis dash hvac schematic

[Bill Lampkin]

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

[Steve Huber]

Bill,
What problem are you trying to solve?
Steve

[Bill Lampkin]

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

[Steve Huber]

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

[Bill Lampkin]

Thanks steve