Bad Alternator

[taylordc15]

Went to start my truck and nothing, jumped it and it started right up but no power to any of the guages, do I need a new alternator or could it be something else?

 

[Michael]

Could be the power switch.

 

[taylordc15]

By power switch do you mean ignition switch and if it was bad then wouldn't have failed to start even with the jump?

 

[Scrounger]

If you have no power to the gauges I would look at main power switch. Then power to the panel. A quick test of the alternator is to check the voltage at the batteries with the vehicle off, it should be around 24 volts. Then check with vehicle running, should show around 28.4 volts.

 

[Capt.Marion]

accessory switch possibly, if there was fuel in the lines already. Is your in tank pump running?

 

[taylordc15]

Thanks guys, Ill order a new accessory switch and go from there

 

[Capt.Marion]

It would be better to pull out the multimeter and make sure that there isn't just a busted wire or something before you go off and order a new switch.

 

[Michael]

Actually, the starter button shouldn't have worked if the accessory switch isn't working. You are going to have to do some more trouble shooting before you start replacing parts. Do you have 12.5 volts across each battery with the motor off? If not, you will need to recharge them before you go any further. About 14 v across each battery with the motor running. Are you getting 24 v on one of the leads to the accessory switch?

 

[bottleworks]

Don't throw parts at your problem. Isn't the accessory switch a DPST switch? One pole could have failed. If that switch has failed, the alternator will not charge. You need to use a multimeter and get the wiring diagram out. You can download a diagram @
http://www.steelsoldiers.com/index.php?name=PNphpBB2&file=viewtopic&t=20673

 

[taylordc15]

OK, the batteries were dead. I charged them and started running through the trouble shooting steps from the -20. I have 24v coming into the alt but nothing coming out. I would assume that my alt is bad. The next step in the -20 is to replace cable 2. I am not understanding this, isn't that the cable thats should be sending 28v out of the alt? How does replacing it do anything?