So Im trying to wire some accesorries in my car, a few gauges, wideband 02 sensor, shiftlight etc etc

At first I was trying to run a power dist block straight fomr the battery with a switch inline, that didnt work because of a problem just like this one

Heres my problem

Im testing this now on my CONSTANT POWER radio wire (connected to radio I jjust tapped in), I check it with my multimeter and it says 12.68 or whatever, as soon as I touch that wire with the power wire from any of the gauges to try and light them up the power drops to 7.44

I figured I had them grounded ****ty, so I gave every gauge its own ground on the center console skeleton, still no dice.

Whats causing this?

 

 

adding resistance in series causes the voltage to drop.

 

So how do I fix this? I ran a line straight for the battery and when I connected anythign the voltage dropped to ZERO

 

V=I*R

So here are your possibilities.
1. you have a defective Guage.
2. You are pulling to much current on the acc line causing the voltage to drop.
3. You have a poorly wired acc line.

Recheck your connections.
Do you have a fuse on acc?
Try hooking your gauge directly to the battery to see if it works.
If it works, measure the current draw, check against manufactures claimes.
Check the connections on the acc line somewhere there could be a bad contact.


*edit*
lol does your car start?
If you connect straight to the battery and it drops to zero maybe your battery is dead. I doubt your gauge could sink a few hundred amps without melting in your hands.

 

The gauge is mint as it works on other things and gives perfect readings

Battery is brand new fully mint

 

That only leaves a poor connection someplace, if there is a fuse in the power line replace it, it may be defective, also how good is the continuity from the "center console skeleton" to the floor pan of the car, [chassis]. and how good is the continuity between the chassis and the batt. neg. post?

You also say the batt. is "mint", is it a fully charged "mint" batt.? 94

 

hmmm I dunno hwo good the ground is there, should I just ground it to the floor, wont be hard, could that cause it

the battery is definetely fine it is brand new, like 5 days old just got it replaced, has 12.75 volts or something and I put it on the charger to 100% before doing anything

There is a cheapy fuse in the inline fuse holder, would that really matter? Should I cut the fuse out of the loop totally?

The fuse I have go BEFORE the switch, like 5 feet from the battery

Thanks so far man

I just dont get why they dont light up at all......

 

There has to be a good ground, or what is happening is exactly what will happen, the same goes for to power side if there is a poor connection, [a lot of resistance at a connection] will also cause the same thing to happen.

Yes a cheap fuse can be the problem, also it should be as close to batt. as possible, [not 5 feet from the batt. if that is what you meant.] and no do not remove the fuse], because the power is connected directly to the batt. I think your problem is grounding, [did you not have some problems with an alarm also]? again check that batt. to chassis ground. 94

 

Ok I will re-do the grounds to the metal floor of the car

My battery -> chassis ground Im sure are fine, I redid it in 4ga to the stock location and added a small 12gauge wire connecting it to another ground above the headlight.

I guess I will pick up some better fuses, these are dollar store ones

I really hope this fixes it

 

uhh, you know the acc. to your radio isn't that powerful.. your pulling too much from it. Use a relay from it, and you'll be fine.

 

It was the grounds for sure, I made them mint on the floor and everything just lit right up

(then burnt because I used 20w 12v bulbs for my gauges)

But it worked mint

thanks guys