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Discussion Starter #1
I just purchased a 72 SS454 chevelle and none of the factory dash gauges work. When I looked at the fuse panel the fuse slot marked gauges was empty. Replaced fuse(10a) and turned ignition switch on; starter engaged before reacing start position. I have to fix this problem before I trouble shoot the gauges. Where do I start?
 

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Sounds like some seriously crossed wires. Take a look at what wires are connected to the S terminal on your starter; it should be one purple fat wire. Remove anything else. How anyone could have wired the gauges to the starter is a mystery to me, but previous owners are a tricky lot.
 

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Discussion Starter #3
JW, Thanks. Will check out tonight. The previous owner did install an MSD box, power coil, distributor and tach. I wonder if he screwed up doing those installs. I have hooked up after market auto meter white face mechanical gauges under the dash to keep me informed, but my goal is to fix everything I can back to original condition, gauge wise.
 

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If you remove the gage fuse does it behave the same way? That is, does the starter engage before the start position? After you release the switch does the starter disengage and stop spinning? Post a little more information.
Not seeing it offhand. Can't see it being a mis-adjusted switch. That's a lot of travel. Like JW says maybe starter wiring. Somebody put the yellow wire on the "S" terminal? The original yellow starter wire is not needed with the MSD box wiring.
 

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Discussion Starter #5
John, When I remove the fuse the the starter works as intended. With the fuse in, the starter engages as soon as you turn the switch to the on position. There is no pressure on the ignition switch when the starter engages in the on position. The fuse was out when I bought the car and I never even looked at the fuse panel until I started trouble shooting the gauges. I will look at the "S" terminal tonight for extra wires. Thanks.
 

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I'd guess the gauges are backfeeding to the solenoid wire somehow.
Check where each gauge - and the light for each - is connected AND GROUNDED. They all need to be grounded to the dash or chassis, and that must be grounded to the engine via ground strap. A light bulb and some types of gauges will provide power through the ground wire - perhaps enough to engage the solenoid.
If you have an ammeter (these are common) carefully check all it's wiring as it carries ALOT of current.
Each gauge except ammeters should be connected to a source on one lead and grounded on the other.The solenoid lead should not be involved at all.
I got rid of my ammeter and installed a voltmeter.

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Discussion Starter #7
283, Thanks for the advice I will check everything especially the grounding. I have found a black wire on the small post (large purple wire on the large post) of the soleniod that may be the problem. Tonight I will remove the black wire and see what happens.
 

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I think I see what you are saying about "big" and "small" posts. Just to clarify things. Typically the older solenoids have 3 terminals on them. A "big" terminal in the center and 2 "small" terminals. One on each side of the "big" terminal. The "big" one in the center is the B+ terminal and that is where the battery is tied to. The inside "small" terminal is the "S" terminal. The S is embossed on the solenoid case. The small terminal, towards the outside is the "R" terminal. Newer modern solenoids only have two terminals on them. The B+ and the S. The R is not needed when GM switched to HEI. Either one will work in your car.
The 72s , like the others, have a purple wire to the S or START terminal. They also have the positive battery cable to the large B+ terminal. The 72 wiring is different than the 71 and earlier cars in this way. The 72 has one other wire on the large B+ terminal. The wire has a large eyelet on it. It is a red wire but could look black on the lower 8 inches of it. This black area is a fusible link. This unique red wire runs up to the horn relay located next to the brake booster on the 72. The wire is what provides power to the car's internal wiring. This is the basic wiring without caring about the amp gage.
Take a look at things before you start pulling things apart. It will make things easier to figure out.
 

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Discussion Starter #9
John, The solenoid is wired as you said in that the large post has the cable from the battery and a large guage wire (purple/red in color) the "s" post next to the motor has the black wire. The other small post on the outside of the solenoid (towards the fenderwell) has no wire. From what you are saying I have the correct wires on the right posts, I think? Somehow I am still feeding current to the solenoid when the fuse is in and the key is in the on position.
 

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I think you should take a good look at where those wires go to. Like JW said, looks like things are crossed. What you are describing is reversed from what I said. May think about chasing the wire from the solenoid B+ terminal. It goes to the one inch threaded terminal on the horn relay. Best way is to disconnect both ends (B+ and horn relay) and measure it with a meter.

**I can't say I see the entire problem (starter running with gage fuse in) but I think I do.
A guess is the pink gage wire is providing power to the ignition switch because of the reversed purple and red.**
 

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Discussion Starter #11
John, Thanks for hanging in there with a guy who knows very little about auto wiring. Tonight I will trace the B+ (Red/Purple) wire from the large post to the horn relay (located next to the brake booster). If it doesn't go there should I make the change and connect it to the horn relay? If the B+ wire is not on the horn relay I have an idea this is the problem that is causing the current feed to the solenoid when the fuse is in and the switch is on.
 

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Or reverese them at the solenoid like JWagner first mentioned. The purple wire (S) on the solenoid is the wire that starts the starter. Somewhere that has a problem. Just looking at the solenoid first and going from there.
 
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