Author Topic: New gauge wiring problem on 67  (Read 4775 times)

SMoon67

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New gauge wiring problem on 67
« on: June 15, 2011, 01:27:42 AM »
I've narrowed this problem down but haven't pinpointed the exact problem yet.  I'm restoring a 67 RS/SS 350.  Right now I'm putting all of the dash stuff in. 

Basically, the problem is this.  To make a long story short, the tach and gauge lights are shorting out when I completely install the gauges (all screws in and tight).  When the pod is loose at the bottom (those  4 screws out) and the bottom of the pod is out a little everything works fine.  But with the engine running, the tach working, and the gauge lights on, when I push the pod in at the bottom to it's mounting position the gauge lights go out and the tach drops to zero.

I don't see anything behind the pod to cause this.  I see no cracks in the printed circuit.  Ground is good.  Harnesses and printed circuit are new.  As I said, everything is working until I push the bottom of the pod in to where the screws will go in.

I had to quit on this today before I got far enough to identify the exact problem.  Obviouisly there is some contact being made that I haven't found yet.  I was just wondering if anyone had seen this before and could tell me what they found.
67 RS/SS 350 4 spd Marina Blue
1988 IROC-Z Convertible
1957 Chevy Belair
1940 Chevy Cabover

flyingskibiker

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Re: New gauge wiring problem on 67
« Reply #1 on: June 15, 2011, 02:55:15 AM »
Kind of obvious, but is the connector coming into contact with anything when the cluster is fully seated?  The turn signal switch connector is usually mounted on one of the braces behind the cluster.  Is that making contact?  Have you measured for voltage at the screws with everything on?   Hmmm....

SMoon67

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Re: New gauge wiring problem on 67
« Reply #2 on: June 15, 2011, 03:41:19 AM »
Didn't measure anything at the screws.  Everything else looks good.  Checked all connectors and wiring to make sure everything is connected well and out of the way.  No wires getting pinched. 

I'm sure I'll find it when I can get back on it, hopefully tomorrow.  I was hoping that with so many restorers on here that somebody had seen this before. 
67 RS/SS 350 4 spd Marina Blue
1988 IROC-Z Convertible
1957 Chevy Belair
1940 Chevy Cabover

68Zproject

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Re: New gauge wiring problem on 67
« Reply #3 on: June 15, 2011, 10:29:10 PM »
I don't know what the back of 67 gauges look like, but if they're anything like 68's, the back of the alt, fuel and temp gauges have little posts coming out of them.  On some of these there is a little plastic insulator that keeps the post from contacting the gauge case.  On mine one of these was missing and caused the post to short against the case.  It's a long shot but......
68Z28

SMoon67

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Re: New gauge wiring problem on 67
« Reply #4 on: June 16, 2011, 09:33:17 PM »
Problem solved.  Original screws mounting gauge housing to plastic pod weren't holding.  Several were loose causing the housing to not ground properly.  Replaced them with similar size screws with a little more bite.  That pretty much solved the problem. 
67 RS/SS 350 4 spd Marina Blue
1988 IROC-Z Convertible
1957 Chevy Belair
1940 Chevy Cabover