When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Can anyone help, I'm the worst with electrical. I have a battery killing short. When I disconnect the battery with everything off and doors shut, then test light from neg lead to neg terminal light comes on.
I pulled all the fuses in the driverside, closing the door between each one, test light still on. I pulled the "haz-horn" fuse under the hood and it turns off.
What all is on the "haz-horn" circuit? (Other than the hazard lights and horn....)
... What all is on the "haz-horn" circuit? (Other than the hazard lights and horn....)
Power to maintain radio memory. Should not kill the battery, but need to know exact current draw. That's why I do not trust nor use test light. I have an $11 Harbor Freight multimeter in the truck at all times.
IIRC, normal idle current draw with everything off is 20 milli-amperes. That's the radio and the ECU memory.
Have you had your battery tested? What is voltage with everything off? Voltage when engine/alt on?
Also disconnect everything from alternator and measure resistance to ground from screw/stud terminal.
Ita a brand new battery. So with truck off accessories off, test the short amps? Then amps while truck is running and everything off?
Also, my tach is acting wierd. With truck runningrnormal it only reads 200-300rpm, while driving reads im guessing 500-1000rpm below where it should.
Originally Posted by RAD4Runner
Power to maintain radio memory. Should not kill the battery, but need to know exact current draw. That's why I do not trust nor use test light. I have an $11 Harbor Freight multimeter in the truck at all times.
IIRC, normal idle current draw with everything off is 20 milli-amperes. That's the radio and the ECU memory.
Have you had your battery tested? What is voltage with everything off? Voltage when engine/alt on?
Also disconnect everything from alternator and measure resistance to ground from screw/stud terminal.
The tack did the same thing about this time last year, but found a short where the reverse light wires were melted to the exhaust pipe, fix and seperated the wires and was fine. Looked the other day and still look fine....
The tack did the same thing about this time last year, but found a short where the reverse light wires were melted to the exhaust pipe, fix and seperated the wires and was tach was fine. Looked the other day and wires still look fine....
Ita a brand new battery. So with truck off accessories off, test the short amps? Then amps while truck is running and everything off?
Everything off and all connections to batt negative disconnected and connected like below so all current passes mutimeter.
Originally Posted by helidriver
...the reverse light wires were melted to the exhaust pipe, ....
Toyota engineers in those days were not as brilliant as its mechanical engineers.
Backup lights, etc taking power from "ENGINE" fuse is a dull move. A short in backup light circuit like you just found could blow the engine fuse which also powers critical circuits.
Also, If I were to mess with the back up light circuit, I would make it switched ground so, worst case scenario, if anything shorted down there, the back up lights would turn on. Truck would keep on running.
MEASURING CURRENT DRAW WITH ENGINE OFF
Last edited by RAD4Runner; 03-11-2021 at 08:49 AM.
Everything off and all connections to batt negative disconnected and connected like below so all current passes mutimeter.
Toyota engineers in those days were not as brilliant as its mechanical engineers.
Backup lights, etc taking power from "ENGINE" fuse is a dull move. A short in backup light circuit like you just found could blow the engine fuse which also powers critical circuits.
Also, If I were to mess with the back up light circuit, I would make it switched ground so, worst case scenario, if anything shorted down there, the back up lights would turn on. Truck would keep on running.
MEASURING CURRENT DRAW WITH ENGINE OFF
I will try this tomorrow and see what I get. Since the radio is on the Haz/horn circuit (since when i pulled the fuse the radio doesnt power) Ill pull it out and see if the short goes away and check the wiring to it. Any idea where the cig lighter socket is circuited?
03-08-2021, 02:29 PM
