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1994 Ford Ranger battery is not charging and the temp/oil gauges spike

While driving at any speed my temp gauge and oil pressure gauge spike well above “H” and stay there. The red battery light sometimes flickers too. The Battery gauge is low. I replaced the terminal to then negative battery cable because It was loose. I have also replaces the alternator. I had the battery checked and it was good, it just at 45% charge. thats why I replaced the alternator. After I did that, It seemed to have fixed the issue. But after 3 days, it has come back again.
Now this morning on the way to work, driving down the freeway, my speedometer jumped to 85 MPH and there was a squealing like noise coming from the engine. Im not sure if the two are related issues.
I would love any advice to take care of this.

First things first. You need to check your oil level. And you need to see if the engine is indeed overheating. Toute Suite. If the engine is overheating, the radiator fan should be spinning like a banshee. You must not drive the car if the engine oil is low (or over the high mark on the dipstick), or if the engine is actually overheating.

Let’s assume the engine cranks and starts fine. And the engine oil is fine and the engine isn’t actually overheating. Then it is likely you have a voltage regulation problem. The dashboard instruments have to have a regulated voltage reference to work properly. If the instruments are wrong, something is likely wrong with that voltage regulator function.

If the engine cranks slowly, then you may still have an alternator problem. Did you have the original alternator checked at one of the big box auto parts stores before replacing it? They’ll usually do that for free if you ask. That’s probably the next thing to do, have your current battery and charging system checked by a tech.

This could be a number of things, but my guess is the problem is the instrument panel voltage regulator. The squeeling noise may simply be that the new alternator, the belt wasnt properly tightened. So have the belt check at the same time you do the charging/battery test.

All great suggestions.

I’d also remove the fanbelt (serpentine belt) driving the alternator and check to see that nothing in that path is binding. Check the serp belt tensioner too. It is possible that that squeaking your hearing is the serp belt intermittantly slipping because it’s not being maintained under proper tension or is being bound up by a component that isn’t turning freely.

You might check for a poor connection in the charging circuit. The molded positive cable from the battery to the fender mounted solenoid has been a problem on Fords.

The belt seems fine, no cracks and it has a self tensioner.
Last weekend I took it in and had it checked finally to see what was wrong. The mechanic said he checked all the cables and that the alternator test was bad. He said that when he disconnected the alternator the gauges went to their normal position. So he said I needed a new alternator.
So I went out and replaced it for the third time and it still isn’t working. Battery is as 12.3 volts even with the engine running.

Looks like I need to check the instrument voltage regulator next. Any ideas on how to do that.

Im a noob when it comes to car work so I am confused as to how the instrument voltage regulator can affect the battery charge from the alternator.

Just an update. I had my alternator bench tested today, It and the attached voltage regulator are good. Auto zone even threw in a new battery to make sure that was not the problem ( I had a 2 year old battery from Auto zone).

I have noticed that at times when I press the clutch, the gauges return to their normal positions.

Solve the charging problem & the other probs will go away.
A few years ago i had the same problem with my 97 Explorer & a quick look at my FACTORY charge circuit wiring diagram told me there was a fuse to check. Popped the hood & checked the fuse in the power distribution box. Sure enough the fuse was blown. The fuse connects exciter voltage from the starter relay to the internal voltage regulator in the alternator. No exciter voltage & theres no charging.

Pop the hood & remove the plastic lid from the power distribution box and flip it over.

Is there a listing for Generator or alternator or charge circuit or some such?

I dont have wiring diagrams for a 94, but on a 91 theres a 15amp “fuse link"cartridge” instead of a fusein the power distribution box.

“I have noticed that at times when I press the clutch, the gauges return to their normal positions”
@Joshd–this sounds as though the ground strap between the engine and the body is either broken or not making contact at one end or the other due to corrosion. Stepping on the clutch completes the ground that is missing between the engine and the body and chassis. The engine is held in rubber mounts isolating the engine from the chassis. Therefore, an electrical connection must be made between the engine and the chassis. One thing you might try is to take a jumper cable and clamp one end to the negative terminal of the battery and the other end to a good ground spot on the body and see if that clears your problem up. If it does, look for the bad ground strap.

On my 97 the fuse is listed strangely enough as "Generator/voltage regulator.

Ok so I used a jumper cable and connected my engine to the frame and there was no change. BUT, out of curiosity, I connected the cable to the alternator and frame and now everything is good. Knowing this, any Ideas on what grounds the alternator? After spending so much time on this Im down for soldering a little wire to the alternator and frame.

O and a mechanic shop had it in for the last day and kept telling me that it was a bad alternator even though I said I replaced it and had the new one bench tested.

The alternator grounds through its case. The case is grounded to the engine through the mounting bracket. The engine is losing its ground to the frame or the alternator case is not grounding to the mounting bracket or the mounting bracket is not making ground to the engine block. Make sure there is a good ground between the engine and the frame–perhaps a ground strap is missing. I think your troubles will be over.