Voltage going to pump is only 8.4V. Should be 12V This is on a 1989 c1500. Anyone have any idea of what the issue is?

 

bad ground...shorted relay..low battery..ignition switch...

 

Ihave cleaned the grounds and the battery is new. I will take a look at the relay and ignition mod

 

the fuel pump ground on the frame?...check that good..then i'd look at the relay next

 

Ichanged the puel pump relay today with no luck. Still won't start. The only thing left is the ignition control switch. I cannot find this switch. I have looked under the dash and I do not see this part for this truck that is listed on the auto parts websites. Help me locate this part.

 

its on top of the column...how many volts going in to the relay?

 

Did you by chance disconnect the fuel pump and test it's voltage? Because if it is drawing too much juice then you will get a bad reading at the pump. Basically what I am saying is to isolate each part as you check it, then you should be able to see what is drawing all the volts down. Then if that doesn't come back with anything, I would go along the Power wire and check for weather cracks and possible wear through the wire and corrosion. If you find a spot, Check to see if that is what it is, then replace even if it isn't what it is just to make sure that it will not become a problem in the future.

 

Only 8.4 volts comming out of the connection that plugs to the Fuel pump. There is 12 V going through the relay.

 

I would check the wiring to the pump next.

 

are you checking it plugged in?..if you have 12 volts with the pump unplugged and then lose the voltage when you plug it in,the pump has high resistance or its ground does