Hello everybody,
I have a 1998 k2500 Silverado with a 4L80E.
My question: what wires get voltage on the neutral park range safety switch (the one that's mounted onto drivers the side of the transmission) . I can't seem to get the right information on different schematics. Some schematic say that a purple wire gives voltage and there's others that show a yellow wire going to the switch. Which one's correct or do they both see voltage...
Greetings Ranchtruck805,
@xXxPARAGONxXx beat me to it, but we're in agreement that the General's
Factory Service Manuals are by far the best documentation available.
I'm having a no start issue on my truck but I have started to hone in on the issue which is somewhere in this area. If I apply direct voltage with a jumper wire in the fuse box where the starter relay goes, the truck turns on but I'd like to turn my truck on with my key thank you.
That's a good troubleshooting approach, for you have eliminated everything
after the
Starter Relay from the troubleshooting table. Here's a few troubleshooting tips in
this area that you might find useful:
1) I took a bird's eye view pic of the Underhood Fuse/Relay box. If you look closely you
can see that all the big square relays are the exact same part number:
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This is a troubleshooter's delight, for we can substitute a suspect relay with a known-good neighbor
in order to figure out if the problem is the relay itself vs. something upstream feeding it.
And here's the legend on the underneath of the cover for the Underhood Fuse Block:
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Let's assume that you swapped the fuel pump & starter relay. If the problem follows
the relay, then we have the proof we need to buy the replacement with confidence.
On the other hand, IF the problem stays in the Starter Relay socket, then we
need to figure out if we are experiencing a 'control voltage' to the relay issue vs a
'power to solenoid' issue? In order to make this easier to troubleshoot, here's the
same sheet, but crayoned up 2 different ways:
Starter Relay circuit, Control Side
{Underhood Fuse 6 > Ignition Switch > IP Fuse 8 > Neutral Safety Switch > Starter Relay Pin 86 > Pin 85 > G105}
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Note: Colored the involved schematic lines to match color code
Starter Relay circuit, Power delivery side
{Underhood IGN A Fuse 6 > Starter Relay Pin 30 > Pin 87 > Starter Solenoid}
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Note: Colored the involved schematic lines to match color code.
So now to figure out if the Starter Relay Control Circuit, *or* the Underhood IGN A Fuse 6 Power to Starter Solenoid circuit
is bad. I know that you've already jumped +12v power to the socket for Pin 87 & it started,
but did you do this straight from the battery, or did you jump from Pin 30 to Pin 87?
If jumpering Pin 30 to Pin 87 works, and (temporarily) swapping in the Fuel Pump relay
doesn't fix it, then working through the control path is going to locate the root cause of not
being able to crank the engine over from behind the wheel.
Best of luck!
