Please help

[Samantha Adcock]

I have a 99 GMC Sierra 1500 and I'm getting no power to my coil I don't know where the fuse is or if it has one I think if it does it's popped and I can't locate it or is there a relay what else could have went wrong these are all the codes it popping up

[Jsdirt]

You've got one or more blown fuses there, or open wires. When in doubt, check ALL fuses. You can do this quickly and easily without removing them with a test light connected to a good ground. Touch the tip of the test light to the tiny metal tabs on top of each fuse on either side of the amperage number - if it lights on both sides, the fuse is good, so no need to remove.

 

Keep in mind, certain circuits will only have power when activated, like running or headlamps, or wipers. You'd have to turn those on to check those fuses. Or, just remove those ones and visually inspect them.

 

If all the fuses are good, now the real fun begins. Sifting through 100,000 miles of wiring to find the open. The wiring in these trucks is such garbage (worse from '07-up). Wires can and do break inside of intact insulation! You have to grab a section of wire and tug on it with a hand on each side. If it easily tears in half, that's where the break was.

 

Best course of action in that case is to grab a wiring diagram. Everything costs money these days - no way around it. That's the world the automotive industry has created for themselves. It is what it is. AllData DIY is pretty good. For about $15 you can get a years worth of access to a bit of information, including wiring diagrams that you can print and take out to the vehicle with you. That will make the job go from almost impossible, to very doable. Look at all the codes you have, and find a power or ground that supplies every one of them. If you find the common denominator, now you only have to focus on that one (or 3) wire(s), or one circuit.

[asilverblazer]

Start with fuses but a quick visual inspection for a rodent eating up wires would be easy enough too.