Electrical Issues, Truck won't start and cabin acts like there is no power at all
09-05-2009, 02:42 PM
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Electrical Issues, Truck won't start and cabin acts like there is no power at all
Hi there. I have a 93 F150 with the 5.0 that I use to haul firewood, stuff home from Lowes, etc.
Since I've owned it, occasionally it acts like it has an electrical problem. The starter won't engage and the truck won't start. This can also be accompanied by the "dinger" that alerts you your keys are in and the door is open sounding like it isn't getting enough voltage.
eg, from "ding, ding, ding" to "diiinnnnnggggg.....dinnnggggg....diiinngggggg "
Usually after enough cursing and trying, the truck will pull its head out of its butt and start up with no more issues.
The battery is good, and it just sat on a charger over night to make sure. My multimeter says its putting out 12.5 volts while hooked up to the truck with the keys in it and in the ACC position, so I think this means we can probably rule out a short.
It started doing it the other day, and hasn't stopped though. Checked all the fuses and they all ohm out just fine. Cleaned the battery terminals and connections just to be sure.
What its doing now is acting like its not getting any voltage to the cabin at all. Lights don't work, radio doesn't come on, doors won't unlock, windows don't go up and down, the AC fan doesn't do anything, and when you put the key in and turn it the gauges don't move. I would assume these are all on different fuse circuits, which is what confuses me. And shouldn't the door locks work even when the key isn't on? So it doesn't seem like its the accessory relay not engaging when the key is turned to the halfway point.
I also found a big problem. Some moron who owned the truck before me installed a Bulldog security system. And, to make things even more awesome, they had no idea what they were doing, tons and tons of electrical tape abound. Its also unplugged, what looks like the +12 and neutral wires were just hanging there. I'm hoping this has always been like this, and the truck will start without it plugged in.
Before I go tearing into this beast, I thought I'd come and ask hoping that this was perhaps a common issue, and was a relay that goes bad, or something else of the sort.
I don't know alot about trucks, however at my day job (well actually third shift, but you know) I'm an electronics technician, so you don't need to worry about dumbing things down too much for me.
Any help would be appreciated, thanks guys!
Since I've owned it, occasionally it acts like it has an electrical problem. The starter won't engage and the truck won't start. This can also be accompanied by the "dinger" that alerts you your keys are in and the door is open sounding like it isn't getting enough voltage.
eg, from "ding, ding, ding" to "diiinnnnnggggg.....dinnnggggg....diiinngggggg "
Usually after enough cursing and trying, the truck will pull its head out of its butt and start up with no more issues.
The battery is good, and it just sat on a charger over night to make sure. My multimeter says its putting out 12.5 volts while hooked up to the truck with the keys in it and in the ACC position, so I think this means we can probably rule out a short.
It started doing it the other day, and hasn't stopped though. Checked all the fuses and they all ohm out just fine. Cleaned the battery terminals and connections just to be sure.
What its doing now is acting like its not getting any voltage to the cabin at all. Lights don't work, radio doesn't come on, doors won't unlock, windows don't go up and down, the AC fan doesn't do anything, and when you put the key in and turn it the gauges don't move. I would assume these are all on different fuse circuits, which is what confuses me. And shouldn't the door locks work even when the key isn't on? So it doesn't seem like its the accessory relay not engaging when the key is turned to the halfway point.
I also found a big problem. Some moron who owned the truck before me installed a Bulldog security system. And, to make things even more awesome, they had no idea what they were doing, tons and tons of electrical tape abound. Its also unplugged, what looks like the +12 and neutral wires were just hanging there. I'm hoping this has always been like this, and the truck will start without it plugged in.
Before I go tearing into this beast, I thought I'd come and ask hoping that this was perhaps a common issue, and was a relay that goes bad, or something else of the sort.
I don't know alot about trucks, however at my day job (well actually third shift, but you know) I'm an electronics technician, so you don't need to worry about dumbing things down too much for me.
Any help would be appreciated, thanks guys!
Last edited by lugoismad; 09-05-2009 at 02:50 PM.
09-05-2009, 03:15 PM
#2
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The fusible links either work or they don't there would be no intermediate shorts in them, similar to that of a regular fuse. My first guess would have been bad battery connections but since you cleaned them and still same problem it is probably the old security system that was hacked into the electrical system.
09-05-2009, 04:14 PM
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The fusible links either work or they don't there would be no intermediate shorts in them, similar to that of a regular fuse. My first guess would have been bad battery connections but since you cleaned them and still same problem it is probably the old security system that was hacked into the electrical system.
See the part about that that doesn't make any sense is that the security system wasn't plugged in to power. So...I'm not really sure how it could just quit working if it didn't have power before and doesn't have power now.
But, who knows... I may try removing it and seeing where that gets me.
But...I think its not part of the issue, because like I said, EVERYTHING doesn't work. If it was just the truck not starting, I'd be willing to blame the security system. But literally nothing is working, the radio, windows, etc. I'd even believe if it the windows and locks didn't work, since I'd assume they were routed through the security system. But the radio?
09-06-2009, 02:57 PM
#4
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Most of security systems prevent vehicles from normal operation even with no power. I guess you'll have to trace all wires from that system to figure out how it cuts the power. They could make it "cut" the truck grounding somehow, which would result close to what you describe.
09-08-2009, 07:56 PM
#6
Senior Member
If it starts up fine with a jump then you problem lies between the battery terminal and cables. Depending on where you hooked up the ground you might just have a bad ground wire.
