alternator or starter dead

[daniel3507]

went to start my truck and to find it wouldnt start. turn the key and hear one click and nothing. replaced the battery with an Interstate with an 18 month warranty and 85 month pro rated warranty and it does the same thing. i cant figure out if its the alternator or the starter though. the started was replaced a few years ago so i dont think that would be it but im not too sure. if it is the alternator is there any harm in replacing it with a higher output one? im not running any special electronics or anything. just a PA system with sirens but i am thinking about a CB and train horn

 

[shadetree]

First, your current alternator is just fine, no need for a larger one.

If you installed a new battery, and the starter doesn't turn the engine over, a couple things: dirty/corroded battery cable connections to the battery, fender relay, or starter.

The cables themselves can be bad. Look for corrosion under the insulation at the battery terminal connectors. Make sure the battery cable to the starter is in good shape.

If the terminals are clean and tight, and the cables are solid, then you may have a bad starter. You can try jumping the large fender relay terminals with a jumper cable. Either use one side of the cables, or connect the two ends of the cable to make one wire, then jump the terminals. This feeds voltage directly to the starter, and bypasses the relay. If the starter doesn't turn, bad starter.

If the starter now turns the engine, the fender relay may be bad. There is a small wire going to the relay. This wire comes from the ignition switch. You can use a wire to jump from the positive side of the battery to the small terminal. If the starter now spins, you have a problem with the ignition switch or the wire going to the switch. If it doesn't spin, possible relay problem.

All the alternator does is keep the battery charged, it does not affect engine start. If the alternator is working, there will be over 12.8 volts at the battery with the engine running, usually 14 to 14.5 volts, but not over 15volts.shady

 

[valleyvinyl84]

+1
I couldn't have said / explained it any better.

 

[daniel3507]

thanks alot shady. tomorrow i'll push it out of the garage and try what you mentioned. would be alot easier if the Bronco wasnt next to it in the garage since i cant use it to jump it. haha

 

[Sunk]

+1 to what shady said. I have a few issues with the fender mounted relays. When checking the connections on it, be careful. It's very easy to strip the copper threads of those terminals, which doesn't help.

 

[daniel3507]

well i went out to to what shady had said, and the damn thing started right up before i even did anything. any thoughts on this? haha.

 

[valleyvinyl84]

I'd change the relay still it may on it's way out. My B2 had the same problem for about a week then the relay quit. Change it while your truck still starts.

 

[shadetree]

well i went out to to what shady had said, and the damn thing started right up before i even did anything. any thoughts on this? haha.

Clean and tighten all cable connections.shady