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Discussion Starter #1
I've got no power to my gauges. None of them are working except the speedo and clock. The clock has a separate power connection. I also don't have dash lights, which tells me I don't have power to the dash period.

Now for the fix...there are three ground wires coming off the left side of the gauge cluster, as you look at it, and down below. The three have circular connectors at the end, telling me they bolt to something. The question is: where do I ground them?

Thanks.

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Sean Thomas
TC #907 ACES #4468
1970 SS 396
 

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Sean
Somebody will have to correct me if I'm not quite right on a 70 gage car.
On the 71/72 idiot light car, there are dash supports coming down on both sides of the access panel. This is right below the steering wheel. On the left support, right above the e-brake, there are holes in the lower part of the support. The dash ground screws into those holes.
 

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I’ll try to explain the location of the ground wire terminations according to the assembly manual.


  1. <LI> Connects to the metal ground strap at the windshield wiper switch. Under the lower of the two drivers side switch mounting screws. Insures grounding of wiper switch and headlight switch.

    <LI> Connects to the back of the instrument cluster. Under one of the screws not used for the circuit card. Ground for the dash and signal indicating lamps, fuel and water temp gauges and clock.

    <LI> Connects to the parking brake assembly. Under a screw located on the main body of the asm. Behind the brake release lever shaft. This is the source of the ground and is the longest of the three wires.
Hope the above makes sense.

The gauge power is supplied via a fuse in the fuse block. The bottom right hand fuse marked gauges (I’m sure you already know that). The fuel and water temp gauges require a ground at the cluster for correct operation. The oil lamp doesn’t ground at the cluster and should work. If the lamp is good, the gauge fuse is good and the switch is connected. The AMP gauge does not ground at the cluster nor does it use gauge power.
 

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The information is in the 1970 Chevelle, El Camino & Monte Carlo Assembly Manual. It has illustrations and instructions used on the assembly line. You may already have one.

The info is found on several pages. UPC 12 sheet B3 illustrates the light switch, note the ground strap. UPC 1 sheet B7 illustrates the windshield wiper switch. Box 13 shows the screw for the ground wire from the INST PNL WRG HARN. UPC U35 illustrates the PARK'G BRAKE BRKT ground connection. UPC 12 sheet B8 Inst pnl wiring harness 13857-867(Monte Carlo same as SS option) note the circled #5 CLOCK ATTACH SCREW. The last ground wire connects here. You can use any screw that will make direct contact with the metal back of the cluster.

UPC 12 sheets D13 Wiring diagram for 13857-67. Not the optional gauge cluster however the grounding connections are the same as the Monte/SS production cluster. Upper right shows three ground wires *PARK BRAKE and *CLUSTER. The third CIG LTR is the wire with the large 1" hole. You likely knew that. Also note these three wires come from a common junction with four additional wires connected, one each for the *W/S WIPER SW., the RADIO CONN., the HEATER CONT. LP. and COMPT LP. (Glove box)
 

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Discussion Starter #6
Thanks a bunch Elree!!

I dug through the manual and found the references. The thing that really stumps me is that ground is ground. It doesn't matter where you ground at, as long as it's a good one. Can't finger it out...

I had all three grounded at the ground strap connected to the windshield wiper switch and had no power to lighting or gauges. I moved the long one over to the park brake and got power to all the lights, and the fuel gauge started working. I left the two smaller ones at the wiper switch and the ammeter and temp gauge aren't working. Actually the temp gauge max'd out to an 'overheat' reading.

Any suggestions on the ammeter, and why it's not working? Or, for that matter, why the temp gauge is max'd out now??


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Sean Thomas
TC #907 ACES #4468
1970 SS 396

[This message has been edited by gorbe (edited 09-13-2001).]
 

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Is the problem cluster factory installed? Did you installed it and the under dash harness? Is the under hood amp gauge wiring in place? The factory amp gauge wiring has fusible links, check them.

The problem with the temp gauge may be a bad ground. The two vertical terminals of the gauge should have a resister across them (it is under the circuit card) the bottom terminal needs to make contact with the metal back and ground.
 

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Discussion Starter #8
This is a factory installed gauge cluster but I've just completed a resto and am trying to get everything working. Where is the fusable link for the ammeter?

I have no idea what I'd be looking for on the temp gauge for the resistor across the vertical terminals.

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Sean Thomas
TC #907 ACES #4468
1970 SS 396
 
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