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