I bought the car used with some issues. The tach was reading way off (really high) and when I turned the headlights on all the gauges went buggy.
I ordered a new instrument cluster (140 mph) out of an 89. A new headlamp switch with connector and pigtail, and a new dimmer switch.
I tore out the instrument cluster and dash to check the wiring. The plug to the Multifunction switch had been replaced by a mechanic (the previous owner told me about it. He said he had paid over a thousand bucks to have a mechanic trace down a short). The replacement had white wires that were crimped into the existing harness.
The headlight switch wiring was correct (I lucked out and found a KLM 87 Mustang wiring diagram manual) with the exception that there was a light blue/black striped wire spliced into the red/yellow striped wire that goes to the multifunction switch. I checked the wiring diagrams and realized this was the power lead coming from the fuse block that was supposed to go to the fog lights (which are no longer installed). When I spliced in the new headlamp switch connector I omitted the LB/BK wire. I installed the new dimmer switch and instrument cluster and connected the battery back. At this point everything worked fine except the low beams. Flash to pass, high beams, turn signals, guages are all fine but no low beam headlights.
So I disconnected the battery and spliced the LB/BK wire back into the R/Y wire and voila..headlights and all is working well.
I have no idea why this is working as the power provided by the fog light wire is on the outbound part of the headlamp switch and in theory should not be affected by the switching. In other words this circuit should be hot without the headlight switch.
I disconnected the LB/BK wire from the R/Y wire as I want the car wired correctly to avoid any problems down the road.
Any suggestions as to why someone would wire it this way? Why is this working? Any help would greatly be appreciated.
Also, Does anyone have a source where I can get the replacement connector to the MF switch? Preferably with the correct wire color and not just white wires.
I ordered a new instrument cluster (140 mph) out of an 89. A new headlamp switch with connector and pigtail, and a new dimmer switch.
I tore out the instrument cluster and dash to check the wiring. The plug to the Multifunction switch had been replaced by a mechanic (the previous owner told me about it. He said he had paid over a thousand bucks to have a mechanic trace down a short). The replacement had white wires that were crimped into the existing harness.
The headlight switch wiring was correct (I lucked out and found a KLM 87 Mustang wiring diagram manual) with the exception that there was a light blue/black striped wire spliced into the red/yellow striped wire that goes to the multifunction switch. I checked the wiring diagrams and realized this was the power lead coming from the fuse block that was supposed to go to the fog lights (which are no longer installed). When I spliced in the new headlamp switch connector I omitted the LB/BK wire. I installed the new dimmer switch and instrument cluster and connected the battery back. At this point everything worked fine except the low beams. Flash to pass, high beams, turn signals, guages are all fine but no low beam headlights.
So I disconnected the battery and spliced the LB/BK wire back into the R/Y wire and voila..headlights and all is working well.
I have no idea why this is working as the power provided by the fog light wire is on the outbound part of the headlamp switch and in theory should not be affected by the switching. In other words this circuit should be hot without the headlight switch.
I disconnected the LB/BK wire from the R/Y wire as I want the car wired correctly to avoid any problems down the road.
Any suggestions as to why someone would wire it this way? Why is this working? Any help would greatly be appreciated.
Also, Does anyone have a source where I can get the replacement connector to the MF switch? Preferably with the correct wire color and not just white wires.
