1997 gmc sierra 1500 350

[grimace007]

hey guys im trying to help my neighbor out while hes at work his truck all the sudden wont crank over....

so far i have checked the starter, its good.
checkk power in and out of all fuses. good.
swapped the relays around to no avail.

now im hoping to test the ignition switch. but i dont have a wiring diagram and dont know what wires to jumper. and dont want to risk popping fuses and doing more harm than good by guessing.


i have the steering column cover off.

if jumpering the ign switch does not work what would my next check be? crank angle sensor possibly?


thanks from dallas.

Brian

[bradrhale]

will not not even roll over or just not fire?? if i were you, i wouldnt jumper anything over in the column. that would be one of the last approaches to this.

[grimace007]

it wont crank... after checking it over with my DVOM

all the larger wires except yellow going into the switch have 12+V with the key in the run position... yellow has .03 Volts and does not change with the key turned to the start position..

i wont roll over nothing...


iirc if it was the crank or cam sensors it would turn over but not fire am i right?

i didnt check any of the smaller wires yet, just the thicker (14gauge-ish) wires

[bradrhale]

it will at least turn over. check and make sure your battery is still good enough. then check to see if your solenoid on the starter is still good. does your cluster come alive when you turn the key to the on position?? manually check your relays instead of switching them around. that has never worked for me real good. double check your fuse panels both inside and outside the truck.

[grimace007]

everything powers on the way it should when the key is turned on.

but the starter does nothing when the key is turned into the start position..
**** the radio even turns off while it in the run position...

how do i manually check the relays what posts do i test and what resistance should they have?

ive tried another known good battery no luck.

i took the starter to vato zone and had it put on theyre tester.. tested 3 times all times passed just fine.

double checked all fuses... all have power on both sides
<-- is what i need

it has to be something simple the truck was just fine never showed any symptoms then last night all the sudden it wont turn over but everything else works fine.

[bradrhale]

have you checked for a good ground?? it might be in the ignition switch but rule out the simpler stuff first. the post for the solenoid wire didnt turn when you put the starter back on did it?? if that post ever moves just a little, it wont do anything until you take the wire off and tighten it back.

[grimace007]

nope that post was good and tight. cleaning the ground w/ a wire brush was the 1st thing i did.

[bradrhale]

do you have any voltage to that post when you turn the key to start?? most of the time, you can take a relay and pull it up just a little out of the socket and test for voltage. read the top for the diagram and it will tell you which is the contactor side.

[grimace007]

i dont have a helper so i cant test the solenoid wire till this evening ill go test the relays in/out and reporrt back with my findings

thanks for the help so far

[bradrhale]

we're tryin anyways. we will get you figured out one way or another. like you said, it is something simple and just got to narrow it down.