Wednesday, November 4, 2009

Instrument Cluster Removal

Note: Updated to reflect no need to cut wires going to light bulbs in the gauges.

I've got a couple of problems with the instrument cluster - burned out indicator bulbs, backlighting bulbs, and the odometer doesn't turn when I drive down the road.

There are 6 Phillips screws around the perimeter of the cluster.  It will slide out, but will be held by the odometer cable, the trip reset cable and a mess of wires.  To release the trip reset cable, get under the dashboard and find the knob.  The knob is held onto its shaft by a tiny setscrew.  Loosen the setscrew and slide off the knob.  The nut holding the shaft has two tiny vertical slots.  You may have a better idea or a specialized tool, but I put the blade of a small flat-blade screwdriver in the slot and gently tapped it.  It came loose and I took off the nut and the cable is now loose.

Now on to the wires.  In a more modern car, there would be a giant connector that would disconnect all of the wires from the instruments in one shot.  In 1973, not so much.  Some of the wires are connected to the instruments with push-on spade connectors.  Some of the wires do go to a normal connector.  Several other wires are hardwired into the wiring loom and go right into the back of the gauges.  Let's examine the three instruments in turn.  I've read other blogs that say to take pictures of the wires so you can get it back together later.  I took pictures and drew each wire's color and position.

Left-side instrument: Brake light, oil light, gas gauge.  This multi-function instrument has a bunch of wires and luckily they're easy to handle with spade connectors and sliding out the small bulb holders.

Center instrument: Tachometer, left and right turn indicators and high-beam indicator.   This one has a connector that unplugs, some spade connectors, and one light bulb wire that goes to the wiring harness

Right instrument: Speedometer, odometer and trip odometer.  This instrument only has 4 wires.  One has a spade connector for ground,  and three light bulb wires.

There is a cluster of 7 Black/Blue wires that tie into a connector also.  These are the instrument backlight wires.

Well, that's it!  The funny thing is the car starts and runs without the instruments installed at all.  Try that in a car today with a dozen computers running everything from the engine to the navigation system.