electrical short

scrapper · Dec 23, 2017

I am having fits with my truck so I was trying to find the electrical problems. I hooked up a test light between the negative battery cable and negative post. It lit up, so I start pulling fuses inside under the dash and nothing. I pulled the fuses in the engine compartment and it went out. The fuse was 40 amp fuse panel fuse. I am not sure but have tried looking everywhere.I have about half of the engine compartment wiring harness unwrapped. I have not found any bad wires. I have taken the dash apart a bit, still need the take the gauge cluster. I am thinking it must be in the truck because when I unpluged the wiring harness the test light would not light up. I do not know much about electrical stuff. I did hook up the meter set it to volts and it was reading around 11.90 volts. I would think it should not read anything? I'm not sure. Any ideas on how or what to check. :icon_confused:

lvwill · Dec 23, 2017

This may sound stupid but it happened to me. Some how the glove compartment light switch got screwed up and the light stayed on until it drained the battery. Took forever to actually figure out the problem. Battery drain is usually something stupid that you would never think of. Lots of things in the truck actually use a little power all the time.

scrapper · Dec 23, 2017

I think everything is off. I unhooked a lot off stuff but I will double check when I take the gauge cluster out.

ericbphoto · Dec 24, 2017

Don't forget to close the doors or defeat the door jamb switch to make sure the dome light isn't confusing your troubleshooting efforts.

Spott · Dec 24, 2017

You're measuring what where?

If you take the negative cable off the negative terminal for measurement between the two, you need to set your meter on Amps or milliAmps to get a number that can be interpreted to mean anything. Trying to measure voltage in that position gives you meaningless values.

Remember to set the meter back to volts before measuring voltage across the battery terminals or anything, or you'll blow a fuse inside your meter.

Themechtec · Dec 24, 2017

I agree with Spott.
Clock, radio, etc, all are live. Possible to even have a dead cell in your battery, 11.9 volts is low for a strong battery. Have you had it tested?

scrapper · Dec 24, 2017

It started with several other things and now I'm at the point I have 2 codes koeo 211 and 542. I have replaced the computer and the fuel pump, from other problems. I have found a couple of bad wires in the harness. These did not solve the problem. I am guessing maybe its the icm? I think when I checked the ground at the fuel pump the ohms were around 20. The first fuel pump was pumping but nothing came out, the second one worked good. Truck will not start almost but it seems out of time. I replaced the crank sensor the ground wire had burnt, the timing is ok. I have removed the radio and several other things.The doors were closed. Everything was off. I think maybe there is a bad ground. Not sure. I have half the wiring harness apart but no more bad wires. I dont think either one of those codes would cause the test light to be lit up when it is between the battery and the cable. The battery is probably due and was not quite charged up at the time. Just wondering if I put the volt meter set at dc volts between the negative post and the negative wire should it read 12 volts? I would think it would not read anything but I have no clue about that.

ericbphoto · Dec 25, 2017

If you connect the meter, set on DC volts between the battery negative and the battery cable, with a circuit path in place, you should read battery voltage. That is why the test light lights up. This is normal because there are usually several things that are energized all the time as mentione above - clock, radio memory, etc. but this "open" place in the circuit is where all the voltage is being "dropped". This is hard to explain without a full-blown electrical lesson. If you want to troubleshoot with the negative cable disconnected, then set the meter on amps and make sure the leads are plugged into the proper holes on the meter. In this configuration, you remove fuses one at a time until the current reading (amps) goes to zero. or install fuses one at a time until you see current. This will tell you what circuits are drawing power. This is a good way to find a parasitic drain on the battery. But not much else.

Currently, it is hard to help you because your description of your problems is all over the place. I am sure you are frustrated and confused at this point. I fully understand that. I have been there many times and I'm an electrician with 35 years experiance. My recommendation would be to try to get everything back together the way it should be and start over. Find out exactly what your truck is and isn't doing properly, check for codes, etc. and get your thoughts organized so you can troubleshoot the real problem. Then, I would first troubleshoot with the battery cables connected, using the meter set on DC volts and look for loose connections, etc. or whatever is dictated by the symptoms.

Spott · Dec 25, 2017

scrapper said:
It started with several other things and now I'm at the point I have 2 codes koeo 211 and 542. I have replaced the computer and the fuel pump, from other problems. I have found a couple of bad wires in the harness. These did not solve the problem. I am guessing maybe its the icm? I think when I checked the ground at the fuel pump the ohms were around 20. The first fuel pump was pumping but nothing came out, the second one worked good. Truck will not start almost but it seems out of time. I replaced the crank sensor the ground wire had burnt, the timing is ok. I have removed the radio and several other things.The doors were closed. Everything was off. I think maybe there is a bad ground. Not sure. I have half the wiring harness apart but no more bad wires. I dont think either one of those codes would cause the test light to be lit up when it is between the battery and the cable. The battery is probably due and was not quite charged up at the time. Just wondering if I put the volt meter set at dc volts between the negative post and the negative wire should it read 12 volts? I would think it would not read anything but I have no clue about that.

I just told you what to do. You need to set your meter to DC Amps or DC milliAmps and put it between the negative cable and the negative terminal, and then tell us what it says. If it's under 40mA, or 0.04A, then you're probably good. My '88 used 6mA when off, but I haven't checked my '97.

Some later trucks had a system that would shut off a number of systems after a period of time, to save battery, but I'm not sure what year that was introduced. If the meter reads over 40mA, then leave everything in place with the doors closed and the ignition off for an hour, come back without opening the doors or turning on the ignition, and check the meter value again and see if it has dropped significantly.

scrapper · Dec 25, 2017

.02 is what it read. I thought it was not suppose to light up at all.Thanks for the help. It is driving me up the wall. I unhooked the radio the over head console, I was adding cruise and made sure all the wires were unhooked from everything. I was thinking maybe the wiring may have caused something to go wrong.I do need to replace the battery. It has been weak. The battery light goes on and off randomly. I ask a mechanic he said the diode was probably blown. I unhooked the alternator to find out out if it was bleeding back through it. The first time I did the fuse pulling the test light only got dim when I pulled the fuse panel fuse out. I started to strip back the harness at the eec and the plug for the wiring harness on the firewall. I did not find anything but the light went out when I pulled the fuse after I hooked everything back up. I hate messing with the harness but it seems to be part of the problem. One of the bad wires was on the bottom of the icm about 2" from the plug. One of the other wires was the plug for the ground on the engine side of harness for the crank sensor. I will try anything right now. If the ground is bad where are any other grounds, I know two on the driver side fender, one on the firewall, one on the block from the battery, one on the radiator support on the drivers side. I would guess there is a ground wire problem with the code?

ericbphoto · Dec 25, 2017

According to the codes, you have a problem with the crank position sensor circuit and another problem with the fuel pump circuit. It might be a ground problem and it might not be.

You need to concentrate on those circuits and stop getting sidetracked by anything not associated with those circuits. Find a wiring diagram for your truck. This is almost impossible without a diagram. I assume from your profile that this is a 1994 Ranger. What engine do you have? That might make a difference.

The 211 code is stored in memory. It might go away after the battery has been disconnected for a while, unless the problem still exists.

Does your fuel pump run? When you first turn the key on, you should hear the pump run for a few seconds. It does that to make sure good fuel pressure is available. Then it turns off until you start the engine. If it doesn't run, check the fuse, fuel pump relay and inertia switch. Then go chasing down loose connections.

scrapper · Dec 25, 2017

The pump works good. I replaced the relay.The engine is a 2.3.The cutoff switch is not tripped. The two codes are after the battery had been unhooked for awhile. There were a couple other ones but they went away after I replaced the relay, fuel pump, and the computer. Its going to have to wait until tomorrow before I go back out there.We just got a couple inches of snow and its outside in my driveway. I'm not sure what connections could be loose. I guess I will clean the last couple of grounds. I dont see anything wrong on the outside of the harness. I think there would need to be some damage on the outside. I guess it could be a ground wire that burnt inside the harness when the crank sensor ground wire burnt off. I have tried to check it all over from the 2 ends I have started stripping. I used the ohm meter and got a reading on the ground from one end to the other end. That is how I found the bad spot on the crank sensor ground plug.

The temp just dropped so it may be a couple of days,dark when I go to work and when I get home. Its -2 wind chill and going to get cold.

electrical short

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