Loose grounds can cause some strange things to happen.

[Kern Dog]

In our old cars, being as simple as they are, many problems are diagnosed and fixed with relative ease.
Today I was out in my '70 Charger rowing the gears and loving the rumble and growl. At one point, the gauge panel went dead.
In 2015 I swapped in a Dakota Digital setup. They have been trouble free since I installed them.

I drove back home and as I was growing closer, the gauges started working again. I shut the car off and started it three times to see if they would fail but they seemed okay again.
Later as I was leaving a gas station, the needles of every gauge started doing slow sweeps left and right. This is some default action that they do when a malfunction is detected.
Back at home.....
I planned to remove the cluster. First thing was to remove the steering wheel. 5 Allen screws and it is off. OOoops! I need to disconnect the battery, right?
The bolt holding the 2 negative battery cables was loose!

The engine started fine, ran fine....The radio didn't indicate any trouble. The heater fan motor spun normally too.
It seems that any other time that I've had a loose battery cable, the terminal throws a spark and the car won't turn over.
What the heck???

 

[Don Frelier]

GM battery the Mopar was telling you something.

 

[64fury74charger]

Great to see your out there feeling better and your car is simply happy to have you back doing what your car was built to do.
Simple and so glad you are feeling better.

 

[moparedtn]

Side posts? Oof, they were trouble even on the cars they came in originally...
Glad to see you out there though! If I can get a little cooperation from the weather
tomorrow, I'll get Fred out for the first time in a month, too.
After the surgery and all that crap, I wasn't allowed to....
I'm still not, but eff that.

 

[Kern Dog]

Side terminals work fine.

 

[SattyNoCar]

See what kinda problems you have when the (stock) ECU doesn't have a good ground. When I see people bash stock ECU's and say how unreliable they are, I always wonder how good the unit is mounted. On my cars, I run a dedicated braided ground strap from the ECU to the (engine) block. At the ECU, I'll run a not and bolt rather then the factory self tapping bolt.

Glad yours was a simple fix. Had something similar with my '93 Dakota. The tachometer isn't accurate to begin with, but one day it started reading all over the place. Turned out the neg cable at the battery had loosened, yet I never had an issue with the truck starting.

 

[66Satellite47]

Ground problems do cause very weird problems. In '72 I had taken the switch panel of for some reason, put it back together, dropped one of the four screws. Figured three was good enough. But started the car and got the stereo type response: switch the lights on and windshield wipers start, the radio was affected and other goofy stuff. I found the missing screw, put it in, all fixed. Later realized that screw was the ground for the switch panel. Wow.

 

[Frank Mopar]

When electrical systems do goofy things you check three things, the ground, the ground and the ground.

 

[Outlawd]

When electrical systems do goofy things you check three things, the ground, the ground and the ground.

I second this^^^A buddy of mine who retired after 50 years of turning wrenches aways said "keep it simple stupid" k.i.s.s.

 

[RemCharger]

Side terminals work fine.

Except when your dash quits.

 

[Rusty 72]

I recently swapped a new motor into a trashed 2006 Mustang I picked up cheap. I know I know...
Car ran great for a week then it would die every time I hit a bump, but only on the highway? When I had it in the driveway it would run great, I could wiggle all the wires and nothing?
Then I found it. The positive cable from the battery to the PDC in the engine. I only had it finger tight.

 

[WileERobby]

Loose grounds ? Oooh... for a moment, I thought this was an agricultural thread

 

[66Satellite47]

My 1st experience with loose grounds was with the electronic voltage regulator. My '70 Barracuda was a dealer demo in June '71. Soon after buying it, noticed that charging was intermittent. Took it to Dodge dealer that had a second shift service crew. Picked it up after dark, after about 2 miles, it again appeared not to charge. Took quite a while to figure out this intermittent problem. The voltage regulator is grounded by the screw that mounts it to the firewall. Eventually figured that the VR and firewall needed to be sanded clean, no paint to act as an insulator. Later I started adding a separate ground wire from the VR to the firewall. Same for the ECU if you use those.