Voltage drop on gauge

[Ribbedroof]

I would ensure that all the grounds are to clean, bright metal. This includes the one at the bottom bolt of the dash. A little corrosion can wreak havoc on a car's electrical system. Also, the firewall to engine ground is often loose/stripped at the thin sheetmetal of the firewall.

 

[Bri guy]

Do you have an idea of where the ground is on the dash? Driver or passenger side?

 

[fleming442]

Dash ground is above the e-brake pedal on 2 10mm screws

Do you have a ground to the fender at the battery, or does it go straight to the engine? That's why most aftermarket battery cables have the yellow butt connector hanging off.

 

[Bri guy]

Dash ground is above the e-brake pedal on 2 10mm screws

Do you have a ground to the fender at the battery, or does it go straight to the engine? That's why most aftermarket battery cables have the yellow butt connector hanging off.

The ground cable goes straight to the block where the headers bolt on

 

[fleming442]

Ok, run one from the battery to the fender, as short as possible with the biggest gauge wire you can.

 

[oldsmobile joe]

I wonder if the guage or part of the wiring going to it is bad....if alt and battery are staying at 14volts with load..... but by the time it gets to the gauge it reads less than 10 volts...something between the alt the guage is the issue?

other than the volt gauge, what are you using to determine the volt readings? are you using a dvom (digital volt ohm meter)?. if your confirming 10 volts at the gauge, then your loosing 4 volts some where. you will need to do some invasive testing. here are some possibilities, bad gauge, bad printed circuit on back of cluster, bad wiring connection anywhere from alternator to gauge, your gauge plugs into a circuit board in the cluster and it could be this.

while it is important to have good grounds and plenty of them, i don't think this is the main problem. a quick check would be to take a set of jumper cables and attach them to your fender and negative side of the battery, this should eliminate any ground concerns.

otherwise we need dvom results to help you further.

 

[Bri guy]

other than the volt gauge, what are you using to determine the volt readings? are you using a dvom (digital volt ohm meter)?. if your confirming 10 volts at the gauge, then your loosing 4 volts some where. you will need to do some invasive testing. here are some possibilities, bad gauge, bad printed circuit on back of cluster, bad wiring connection anywhere from alternator to gauge, your gauge plugs into a circuit board in the cluster and it could be this.

while it is important to have good grounds and plenty of them, i don't think this is the main problem. a quick check would be to take a set of jumper cables and attach them to your fender and negative side of the battery, this should eliminate any ground concerns.

otherwise we need dvom results to help you further.

Using one of these to check it.

 

[roger1]

I say the problem is high resistance in the dash panel floppy circuit board. They are notorious for doing this when they get old and tarnished. The slip in plug to the circuit board is worst place for it. Then, at each bulb connection. Check the entire thing out. The resistance in these boards isn't the best even when they are new and the volt meter commonly shows voltage drops that are only happening in the board itself. It's just a cheap *ss poor design from the factory.
I got rid of mine and went with a Dakota Digital VHX dash. Best $750 I've ever spent on my car.

 

[Bri guy]

Im not gonna be able to spend that much on the car right now. If everything under the hood shows 14volts it should be fine right? Or should i expect issues to follow

 

[roger1]

Im not gonna be able to spend that much on the car right now. If everything under the hood shows 14volts it should be fine right? Or should i expect issues to follow

I understand. It's pretty expensive and this CV has everyone in feeling very frugal. I know I sure do.
I'd take the time to take the dash off and use a pencil eraser on all the connections at the slip plug and at each bulb and gauge location. That could fix you up for quite a while and not cost a cent. One thing everyone has right now is time!
I'm doing spring cleaning like I never have before and come up with many things to sell on ebay. Cash positive things are a side benefit that is really needed right now too.