96 Blazer fuel pump has 2 connectors on it, a 4 prong and a 3 prong. Does anyone have a diagram for these connetors and what they are. I am trying to test for a dead fuel pump but don't know the pin voltages.

Ok I pulled the tank and pump, checked voltage at the pump connector, only getting about 9 volts. Also broke a fuel line connector when doing it so I am going to need a new pump if it is the problem or not now. :grinyes:

Going to do some testing tommorow if its not too cold, going to check voltage at the pump relay in the glove box and see what voltage I am getting there.

The gray wire is the fuel pump 12 volt feed.
You need 12-13 volts on it.
Check with key on fuel pump prime. Or engine crank.
Just key on will not switch voltage to it.
Or jump the fuel pump prime wire to get 12 volts back there.
MT

The gray wire is the fuel pump 12 volt feed.
You need 12-13 volts on it.
Check with key on fuel pump prime. Or engine crank.
Just key on will not switch voltage to it.
Or jump the fuel pump prime wire to get 12 volts back there.
MT


Too cold and snowing to do much testing today, will try in the next few days. I am getting a constant 8 volts back there with the key in the on position, not during prime. I am hoping that it does go up to 12 volts for the 2 sec prime then I will be good. Just curious as to why I am getting the constant 8 volts with the key in on position.

I did get the 12 volts for 2 secs at the relay but could not test at the tank because I was the only one here and could not have anyone turn the key while I watched the meter under there.

Make sure you are checking the gray wire. It is the fuel pump feed.
The fuel gauge wire only should have voltage with key on.
MT

Make sure you are checking the gray wire. It is the fuel pump feed.
The fuel gauge wire only should have voltage with key on.
MT

Will double check voltages when it stops snowing. :grinyes:

This is for a s-10 but your Blazer should be the same as your Blazer.
http://members.troublecodes.net/crunch/96s1043fuel.pdf

Retested everything and am getting the correct voltages, now just waiting on the new fuel pump to come in tommorow and the fun begins all over again. :grinyes:

I guess I was reading my haynes manual plug info backards before and reading the signal from the sending unit. :screwy:

Retested everything and am getting the correct voltages, now just waiting on the new fuel pump to come in tommorow and the fun begins all over again. :grinyes:

I guess I was reading my haynes manual plug info backards before and reading the signal from the sending unit. :screwy:

I kinda wondered about that.
Glad you got it tested out and good luck on the new fuel pump.
MT