Bouncing voltmeter... occurs when truck hits a bump.

[Blacksheep Josh]

Okay, so I got my truck running again. No accessories are hooked up, no subs, no neons, no nothing. Completely "stock".

Battery cables are good. Grounds on engine/frame look good. Added another ground from the body to the battery, and added supplemental wiring from battery to fuse box.

Voltmeter (and everytime voltmeter bounces the headlights dim, so they're doing it together) bounces whenever I hit a bump in the road. If I go over a speedbump, the voltmeter will bounce and all the lights (headlights adn dash lights) will dim.

What can be causing this? So that when I hit a bump the system dims? As I stated before the grounds looks good... Nice and tight. Battery cable on teh positive side that connect the battery to starter has some corrosion but nothing to worry about. Wiring from battery to fusebox/solenoid looks fine and perfect.

So what else can I do/check? I'm outta ideas.

P.S. - Tomorrow I'll be adding extra grounding wire from alternator to battery.

 

[arco777]

Perhaps a stripped hot wire is grounding out against the frame or rubbing on another wire when you go over bumps?

If the short was enough to make a spark, then possibly with key on engine off (or engine on and it's dark out), you might be able to power the system, hood up, and jump on the front bumper repeatedly watching and listening for bouncing loose wires or sparks...

Just a crazy idea! Another thing you could try is pulling fuses for various circuits and find a parking lot with a speedbump or some other bumpy spot, run over bumps with different circuits disconnected...

Not exactly scientific method but it's a thought.

 

[Opera House]

Sounds like a bad ground strap from engine to car body. Try adding an extra wire from NNeg battery terminal to the body.

 

[Anime]

Battery mounted securely? Alternator wiring ok?

I'd suspect a loose wire or connector (or a loose wire in a connector) somewhere.

You might also disconnect the additional ground and supplemental wiring and see if that makes any difference.


If it wasn't showing on the voltage meter and was just the headlights and gauges dimming I'd suspect the headlight switch. It might still be worth inspecting, as it could cause enough draw to blip the voltage if it's messed up.

 

[Blacksheep Josh]

I have added a 4 gauge wire from B+ side of Alternator to + post of battery.
I have added a 4 gauge wire from Alternator bracket to - post of battery.

Only difference is now the voltmeter stays consistently in the low end of things. It won't come up to where it used to sit when it was normal. After work tonight, I'm going to go by Wal-Mart and buy a tester and see where the volts are sitting at different points. I have one at home but I forgot to bring it with me to college. I think I'm just going to have to test everything and see where the problem is.

I did have another idea though, if the headlights dim when the voltmeter dims, that would mean that "failure" of volts is happening along a power wire they both see. Where would that be?

Oh, and the headlight switch was replaced over the Summer, I double checked it a few weeks ago when I was installing a switch for something and it looked fine (it was doing this back then as well)

Also, where is the ground for the dash electronics?? There's got to be one up underneath there somewhere.

 

[Opera House]

I bet you find the voltage at the battery is perfect. AND if you measure the voltage from the NEG terminal to the body you get voltage. The meter basically measures the voltage of the battery to the vehicle body.

 

[BrianDye]

Hm, I would guess something around the alternator, as in loose connections, hell maybe even a loose MAIN fuse on the side of the fusebox under the hood...


(If I may ask, whys your ex stripped now?)

 

[Blacksheep Josh]

(If I may ask, whys your ex stripped now?)

I was in a high speed wreck, I hit a stopped car goign 55... had to replace entire front end (both fenders, hoods, bumper, grill, headlights, even had to weld in a new engine cage on the passenger side) and got super pissed that it was 4 different colros one day. It's actually 3 different black spray paints I used from walmart, was testing them out. Eventually I'll finish priming the whole thing black so it's uniform.

Tested battery voltage, read right around 11.78 or so.

On the way home from work the battery stopped charging, started in the normal range and read right above the 8 volt mark on the meter... ABS light came on, radio shut off, heater wasn't working... Definitely something loose.

Could the battery simply just NOT be accepting a charge??

Also, where is the ground for the fusebox under the hood? I'll go and check all the main fuses tomorrow when its warmer.

Could teh plug that plgus into the regulator be damaged? Or those wires that come out of it? Where do they go to? The fusebox? I'm thinking I might just have to replace that entire pigtail.

 

[BrianDye]

I said maybe the main fuse on the side of the fusebox, because I remember reading 2 threads A WHILE back, months ago, where 2 different members were having simaler problems, like power cutting in and out, then at times not getting ANY when they tried to start it even though the battery was reading fully charged with a voltimeter...

(I had you confused with a different member, cus I wouldda swore you had like a grey '01 sport, lifted and some other stuff haha)

 

[Blacksheep Josh]

Lol, if I get a 4x4 this Summer it'll be lifted, but I want to lower mine, nothign else.

I didn't realize there were fuses on the outside of the fusebox, was that a differnece between the first and second generations? I know of the fuses inside the box but I've never seen anything on teh outside.

I'm going to call around and start working on a new pigtail setup for the alternator. If that's not it idk what else it could be. I know it's something under the hood... it's just got to be. Nothing else makes sense.

 

[explorerguy89]

idk sounds like battery cable isnt hooked up good somewhere or alt cable

 

[BrianDye]

Theres ONE HUGE fuse on the shorter side of the hoods fusebox, it says "MAIN FUSE" or something like that on it, but yea I wanna lower mine too, ive been looking at rims all day now haha

 

[Blee1099]

Another thing to check is the start relay on the fender. See if its cracked or loose.. A bump can cause it to loose contact.

 

[Blacksheep Josh]

idk sounds like battery cable isnt hooked up good somewhere or alt cable

They are, that's the first thing I checked. I even added cables to help with grounding and power transfer. Nada.

Theres ONE HUGE fuse on the shorter side of the hoods fusebox, it says "MAIN FUSE" or something like that on it, but yea I wanna lower mine too, ive been looking at rims all day now haha

Okay, I'll look for this tomorrow. I've never seen anything like this before on it, I wonder if it's on the backside or something.

Another thing to check is the start relay on the fender. See if its cracked or loose.. A bump can cause it to loose contact.

You mean the starter solenoid? It was replaced after my last wreck, but I'll check it to be sure... maybe it did crack somehow... now that I think about it, when I had this battery put in, the assh@le at Autozone let the wrench hit the solenoid and negative post of the battery making a pretty good spark... wonder if this shorted it maybe? Idk, but I'll inspect it tomorrow to be sure.

 

[Blacksheep Josh]

Because the battery is basically dead again, I'm thinking about this... remove my battery, use jumper cables and simply piggyback my battery onto his electrical system so mine can charge. I figure let it charge for about 10-15 minutes then put it back into my vehicle, start it (if possible) and see where the voltmeter is. If it's dancing around I can hook my buddy's battery up to mine and if it stabilizes it's the battery, if it doesn't it's something else.

Basically just a really long battery test... but would it work? I don't see why not...

 

[BrianDye]

Yea, I just looked out on my 2nd gen, its on the firewall side of the box, which should be the same on the 1st gen, it'l be either on the firewall side, or the front end side, not the sides facing the wheels. Haha I sound stupid, but im just trying to be specific, because I cant really say left/right/front or back unless I know what way your standing lol

 

[Blee1099]

I had a similar issue.. http://www.explorerforum.com/forums/showthread.php?t=154397

 

[gmanpaint]

Josh, have you checked the ground strap on the firewall? This definitely sounds like a short. If you have been replacing items in the electrical system, I would look over everything you or someone else has worked on in the past. Most of the time when something electrical goes wrong, it is from when someone has added aftermarket electronics, (trailer harness, amps, lights, etc..) or just didn't install a part correctly.

Another rare thing that can happen is something might be sticking up to high and shorting out on the hood when bumped. Try a slow test drive with the hood unlatched but not all the way down. Look for tell tale marks of arcing on the underside of the hood. Never know, it has happened to me before. Also don't forget to look under the rear of your rig. Some wiring back there could have been damaged as well.

 

[Blacksheep Josh]

I know there is a groundstrap on the fender well on teh passenger side, I was not aware there was a ground strap on the firewall... where is that?

 

[Blacksheep Josh]

Or rather, wehre on teh firewall is it?