Hey guys,

I have a 99 Blazer with a no start condition. "0" PSI measured at the rail. No pump sound from the filler tube when the key is turned on. It will run briefly with starter fluid applied. SO, the logical conclusion would be a bad pump. I would like to check the 12V power to the fuel pump and I am looking for a way to accomplish this without having to drop the tank....at this point in time. I know the Passlock system could be involved here so I want to check the pump out first as the vehicle has been sitting for a while which further indicated a bad pump.

Found this basic wiring diag on the net and was wondering if there really is a "fuel pump test connector" under the hood where I could measure the primer pulse voltage for the 2 sec after the key is turned to on? If not, can I measure it at the "G" pin on the ALCL connector?

Thanks in advance for any assistance.

 

Hello,Hello,Hello
Is there anybody out there?
Just nod if you can hear me.
Is there anyone at home?

Come on now
You know I'm feeling down
Well, can you ease my pain
And get me on the road again

I'll Relax
But I need some information first
Just the basic facts
Can you show me where to probe?

 

Not sure,but to test power etc. get a manual,find what wire supplies power,find it on the frame,nick it,and test. easy?

blazers eat pumps,balljoints,idler arms,and manifold gaskets. do it all with oem parts. good to go 500000000000000000000 miles.

 

the test lead on gm trucks is usually along the fire wall
If I remember right , drivers side
Usually about 8-10 inch long wire with a square black connector on it

 

On my 95 it is located on the drivers side quarter panel. There is a power block where the fusible links connect. Look between the power block and the firewall. There is a black wire there with a black square connector on the end.

 

In case someone else is in need of this info. The terminal just to the left of the FP relay will light a test light in the key on position for 2 seconds (prime) indicating that voltage is probably being applied to the fuel pump in the key on position.



After verifying that, I went to the tank and measured the voltage across terminal B and C on the FP module connector (power and ground to the pump) Measured 12 volts there for around 2 seconds after turning the key to the on position so now I am convinced the pump is bad.



I will now drop the tank and test the pump before I buy a new one...if it won't run with 12 volts directly applied....it is dead for sure.

 

yo i can see you.yeah it hard somti