4.3 gauges go crazy

[hurst1979olds]

This has been going on for awhile but was intermittent and now getting worse. I have a 2000 4.3 4x4 5spd and Ill be driving and Ill see my tach just go nuts and then settle down back to normal. Occasionally It will have a jolt along with it and my ABS, Security light, Brake light will turn on then off. Now just recently Ill be driving and notice my volt gauge fluctuating alot. Going from 14.5 down to 13 then back up and then down to around 12 or so then my tach will go nuts again then itll setlle back down then Ill start seeing the volt gauge moving again. Sometime Ill go days without seeing my volt gauge moving passed 14.5. So i replaced the alternator and it didnt change anything and my battery is about a year old. Im starting to think its my cables. I take my voltmeter and check the voltage from the back of the alternator to the negative side of the battery and it reads a steady14.5 and I look at the dash and its moving around alot. Tell me what you think. Thank for the help in advance.

[gnicholson]

these vehicles had a lot of ignition switch problems that caused symtoms just like yours. thats what i would look at 1st

[foxracing584]

i have the some exact problem with the voltmeter. and only that.... igniion switch? like where you put your key in? or what? i already replaced that when i got the truck b/c i do that whenever i by a new truck i change all locks!

Edit: btw im asking for help to?

[Yogi]

Sounds like there is a bad ground wire somewhere.

[foxracing584]

could it possibly something else except a bad ground?

[Yogi]

Quote: Originally Posted by foxracing584

could it possibly something else except a bad ground?

When you bought it, you prolly replaced the lock cylinder, not the ignition switch. It could be the ignition switch.

You say that your problem is with the voltmeter only. That would also indicate a possible malfunction in the voltage regulator in the alternator. And the gauge itself could also be going out.

I would think that the alternator is the prime suspect, but an intermittent problem is hard to diagnose and pinpoint.

[epiphaknee]

Is your hazard switch in the steering column broken?

Have you removed your instrument panel recently that houses your speedo and tach?

[Bill Wheats]

Just wondering; Does the engine keep running steady when the gauges go crazy?

[hurst1979olds]

somes times it dies. other times it doesnt.

[tspears]

i have the same problem with mine an 01 2dr blazer, every once in a while all of my dash light come on and gauges jump around. mine has never died. and another problem i have i turn my key to start it and it doesnt do any thing. i have to cycle it back and forward a few time's or let it set for awhile and then it starts

[coldsteel187]

you have a bad connection on your hot wire check all the hot connections under the hood.mine done this and a wire came loose on the block with all my hots on it.

[revned2008]

it happwns with me in my 91 Sonoma but just with the gas gauge going from half a tank all the way to full then all the way to empty then stays at empty for a minute. Then it will go half way. I thought it was just the gas going around but when it stayed at empty then i there is a problem

[btownjimmy]

Check the ignition module.