No Spark

[DGisch]

Morning,

I have a 97 Blazer, 4.3 engine, 114,000 miles. NO SPARK!
I have looked at the threads about 97's with no spark.

Sounds like I might have a bad ignition wire harness or a bad ignition switch.

So where is the ignition wire harness located?

How can I tell which is bad?

I have already replaced the coil, ignition module, and camsaft sensor.

[MT-2500]

Welcome to AF.
IGN AND SWITCH WIRING RUNS ALL OVER.
Check for 12 volts to ign modiule and coil and VCM with key on.
Another good place is to check for key on to fuse boxes,
Can you hear fuel pump prime up?
Does engine crank good?
Any check engine or security lights on?
Does all dash lights come on for a bulb check key on?
Where and how are you checking for lose of spark?
Is the dist shaft/rotor turning when cranking?
Is everything else powering up key on?

[DGisch]

Originally Posted by MT-2500

Welcome to AF.
IGN AND SWITCH WIRING RUNS ALL OVER.
Check for 12 volts to ign modiule and coil and VCM with key on.
Another good place is to check for key on to fuse boxes,
Can you hear fuel pump prime up?
Does engine crank good?
Any check engine or security lights on?
Does all dash lights come on for a bulb check key on?
Where and how are you checking for lose of spark?
Is the dist shaft/rotor turning when cranking?
Is everything else powering up key on?

Engine does crank good. No check engine lights or security lights come on.
Fuel pump does not prime up. Dash lights come on. Rotor is turning when cranking. Radio wipers lights come on with key on. I was checking spark from a spark plug ground on a metal engine support and then the coil wire.

[MT-2500]

Does check engine light come on key on?
97 is a bad year on ign switches.
Check all ign on power feeds.
Is the coil and ign module and vcm getting 12 volts ign?
Also go to fuse box and check for power on all ign fuses.

[DGisch]

Originally Posted by MT-2500

Does check engine light come on key on?
97 is a bad year on ign switches.
Check all ign on power feeds.
Is the coil and ign module and vcm getting 12 volts ign?
Also go to fuse box and check for power on all ign fuses.

Thanks for ALL your help. I REALLY appreciate it.

No lights when key is in on position. Fuses appear to be good.
Meter shows 12volts at all those points you suggested.

How hard is it to replace the ign switch?

[MT-2500]

Not to bad to repalace but check things out first.
You should have a check engine and a few other lights key on or bulb check.
No check engine light you have aproblem there.
Did you check both sides of fuses for 12 volts key on or just look at fuse?

[DGisch]

Originally Posted by MT-2500

Not to bad to repalace but check things out first.
You should have a check engine and a few other lights key on or bulb check.
No check engine light you have aproblem there.
Did you check both sides of fuses for 12 volts key on or just look at fuse?

It was the ignition switch. Not bad to replace but wasn't easy. Sure THANK YOU for your assitance.

[MT-2500]

Originally Posted by DGisch

It was the ignition switch. Not bad to replace but wasn't easy. Sure THANK YOU for your assitance.

\
You are welcome.

And thanks for posting back the fix.
Glad all is well and running.