I have a crank no start as said in title, I've replaced starter, the solenoid in the fan shroud, reran starter wire that runs to the battery. I have one other idea that is the fuse but I won't be able to find out until later. I turn it over to start nothing happens my abs light that is on turns off and nothing else turns off. Any ideas? Grounds maybe idk, there is what looks to be a braided ground wire that's broken that runs along the frame and goes up to the cab. Also another wire broke but it ran fine without it (it comes from the bottom back of the engine block and went into the shroud the starter wire came out of)
Greetings & welcome to the GMT400 forum!
In order to get a better feel for whatever ails your K2500, if you could
take a moment and share a brief history of how this truck has functioned?
* Has it ever worked for you, or did you buy it for the right place because it didn't start?
* If it used to work, but quit, how long has it been sitting? How strong is the battery? Fully charged?
* Was it running perfectly & suddenly stopped? Or did it grow more intermittent over time, until it finally stopped responding at all?
* Theft recovery? Recent Accident?
You get the picture. Those of us who try to troubleshoot remotely need as many clues as
you can give us to work with.
****
Alright, a No Crank/No Start situation is normally something straightforward, fixed with a fresh battery,
starter swap, or the tightening of a electrical connector. But if all this have already been double-checked,
let's dig a little deeper.
How about we first identify what specific fuses are involved, and have you check those first? And
if we don't find anything there, then split your engine cranking circuit near the middle, in order to try and figure
out which direction (upstream or downstream) we need to go?
Here's the start circuit wiring diagram for your '98, control side first:
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NOTE: Fuse 6 (IGN A) is located in the "Underhood Fuse Block", whereas Fuse 8 (CRANK) is located in the
Instrument
Panel fuse block. You need
*both*.
If either one is blown, then no joy. Replace, retry. If it now works, why did the fuse originally blow? On the other hand, if it blows again,
then we need to identify what's causing the excessive current draw.
****
To help you navigate the Underhood Fuse Block, I've attached 3 pics: a look at the legend on underside of the dust cover,
a bird's-eye view of actual unit, and finally how the relay sockets are laid out, comparing wiring diagram numbering scheme to
physical implementation.
Note that in this photo I'm actually showing you the Fuel Pump Relay socket, but since all 3 relays on the lefthand side are identical and
the plug orientations match, if you follow the legend and pull the starter relay (upper Left corner in the photo) you should be good to go.
*CAUTION*
The next step involves jumpering 12v power. Unless you are completely confident, capable, and comfortable doing this,
STOP here & take this to a qualified mechanic and let them troubleshoot this.
OK, you still want to proceed? Before going any further, if the truck is an Automatic, it must be in either Park or Neutral.
Parking brake set. Wheels safety chocked. Or enlist a helper with a foot firmly on the brake pedal. And if it is a standard,
it MUST be in neutral. Why all the precautions?
A: Because for troubleshooting purposes we are temporarily jumpering around the Clutch Safety / Neutral Safety Switches,
and if the precautions above are not honored, the engine could turn over, start, truck takes off, folks get hurt, news at 11. (!)
Still here? Alright, one more wiring diagram to look at so that you understand what I am asking you to jumper: (Starter Relay socket, Pin 30 to Pin 87)
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Looking at the schematic, if we were to take a wire and jumper Pin 30 to Pin 87, this will apply
Power from Fuse #6 directly to the Starter Solenoid. IF this gets the engine cranking, then we
now know that we have a Control issue:
* Starter Relay bad, or
* something upstream in the control chain, possibly all the way back to the Ignition Switch.
On the other hand, if the starter *still does not crank*, then obviously head down to the starter.
And as @xXxPARAGONxXx stated, fix the grounds. No broken grounds allowed anywhere in the
GMT400 engine bay.
Actually, it could be argued that you should try to fix any obvious wiring issues *before* trying
the diagnostic step I outlined above.
****
Enough for now, I'll stop here and await a status report from you before going any further. If you
have any questions don't hesitate to ask. And sometimes a photo to go along with the question
is invaluable/saves time.
Let us know what you discover.
Good luck --
