Starter clicks once then whole truck loses power.

Ryan1972 · Post by **Ryan1972** » Thu Nov 20, 2014 2:59 pm

In the process of getting my 1972 f100 that i recently purchased from my neighbor running. I put a brand new battery on this morning and when i try to start it it clicks once then i lose all power in the truck. The only way to get the power back on is to disconnect the battery and reconnect it. any tips on what i should check would be greatly appreciated.

sargentrs · Post by **sargentrs** » Thu Nov 20, 2014 3:33 pm

Grab a voltmeter and start checking cable connections from the battery, through the solenoid and to the starter. Check all connections with key off, then key on, then key in start position. Check at the terminal and the cable ends. Check the battery post, then the cable's clamp on the battery, then the other end of the cable, then the stud the cables bolted to, etc. Also check at the "S" and "I" terminals on the solenoid. Watch for voltage drop at each point during the various positions of the ignition key and try to see which connection is bad. As a side note, solenoid's are notoriously bad right out of the box. Make sure all ground cables are clean and connected securely.

1 Crummyshooter · Post by **1 Crummyshooter** » Thu Nov 20, 2014 4:58 pm

Well...........
If it is dead until you disconnect the battery, something is keeping the battery shorted out. Since it heals up when you disconnect the battery, it must be a relay, that drops out when it loses power. Now there is only one relay in the circuit, the starter relay, it would appear that is a place to start. The starter relay coil should only be energized when the ignition switch is in the start position, so it looks like there is a wiring mistake that is keeping the relay energized. Pull the low current (small) wires off the relay, put a screw driver across the the positive battery terminal and the small terminal next to it on the relay. Should crank the engine, if the key is on it may start, so leave the key off. If it cranks when you short the terminal and stops when you let up, you have a wiring problem. Also since the whole system shuts down when the relay is energized, it looks like a started problem, or a grounded started wire. Disconnect the started lead from the relay, and try again.

I guess in a truck the term is solenoid, not relay.

tac · Post by **tac** » Fri Nov 21, 2014 10:43 am

Did you clean the battery terminals? You should see shiny metal before you reconnect them. If not you have a small connection that allows a small amount of current to flow and as soon as you start to crank the huge amount of current obliterates that tiny connection.

1972hiboy · Post by **1972hiboy** » Fri Nov 21, 2014 7:05 pm

keep it simple. clean the battery terminals and the cables. re-install and make sure they are secured snugly. sounds like a corroded connection at a battery terminal. some times if the old cable doesnt want to sli[p down far enough on the terminal ill use a deep 11/16 socket and lightly tap on the cable to get it to move further down onto the terminal.

Ryan1972 · Post by **Ryan1972** » Sun Nov 30, 2014 4:55 pm

Thanks for the help guys. I found the problem... it was a bad positive battery cable.

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Starter clicks once then whole truck loses power.

Starter clicks once then whole truck loses power.

Re: Starter clicks once then whole truck loses power.

Re: Starter clicks once then whole truck loses power.

Re: Starter clicks once then whole truck loses power.

Re: Starter clicks once then whole truck loses power.

Re: Starter clicks once then whole truck loses power.