Is my alternator bad?

[Afboy143]

So my truck wouldn't start the other day. I went and bought a new battery since my Optima Red Top has been in there for a little over 5 years now. I put the new battery in, wouldn't start. I turn the key and I just hear a clicking noise. I jumped the truck off my mustang- works great! I drove it around the block and all way good. Came back and parked it. Turned the truck off and waited a minute... tried to start again and the clicking is back. I have a feeling the alternator isn't charging the battery like it should. ideas?

 

[techieman33]

take the alternator to a parts store and have it tested.

 

[Afboy143]

That is what I am thinking of doing. I just tried jumping it again to perform the test where you get it running and disconnect the posative to see if it stalls. I couldn't even get it jumped this time. Did I fry the battery??! Oh this is a pain.

I then locked the truck, and pushed the button twice to where it honks. The battery was so low the horn would barely honk.

 

[SoNic67]

If you can measure the battery voltage with the car running, it should be 14.4V for a GOOD alternator. No 13V!
Do not START the car with a depleted battery, it WILL fry the alternator. Even the Mustang one is in danger if you use thick enough cables!
Charge it before with a charger!

 

[Afboy143]

Well I actually just took the alternator to the local Advance Auto parts to get tested (was extremely easy to remove btw) and it tested GOOD. Dang. So there goes that idea. I was explaining my woes to the guys that work there and they said it could be the starter solenoid since it's still original and I have over 130k on the truck.

I will also have my new Wal mart battery tested and my old optima. I will keep all updated.

Edit: I am reading my haynes manual. They sold me a starter relay, and not the solenoid. According to the manual, the solenoid is starter mounted, while the relay I got is fender mounted. Looks like the relay will get changed out tomorrow. Let's see what happens

 

[greasemanicure]

Starting with a jump and with a test-good alternator sounds a lot like dirty battery terminals to me. That would create a high resistance to the current demands of the starter and prevent the alternator from giving a full charge. If you already cleaned the terminals, it would take some more diagnosis.

 

[Afboy143]

Starting with a jump and with a test-good alternator sounds a lot like dirty battery terminals to me. That would create a high resistance to the current demands of the starter and prevent the alternator from giving a full charge. If you already cleaned the terminals, it would take some more diagnosis.

Understandable; however, my terminals are very clean since I was running an optima battery. I cleaned off the little but of crud that was on there and reseated all the wires- still nothing. I am driving the mustang for now, but I will do some testing when I get home. Tapping the starter solenoid and replacing the relay. With it being a '99 with over 130k, normal things like this are bound to go out as I know it's all stock

 

[my98nnj]

Sounds like a bad connection somewhere, being that the horn bearly worked.
Check both ends of all cables from the battery. Make sure the grounds are OK as well at all cables from the positive cables. Look down at the starter for a poor or corroaded connection as well.

 

[Afboy143]

Sounds like a bad connection somewhere, being that the horn bearly worked.
Check both ends of all cables from the battery. Make sure the grounds are OK as well at all cables from the positive cables. Look down at the starter for a poor or corroaded connection as well.

Makes sense regarding the horn. I didn't even think about that.

I will check:

The ground from battery to chasis
The posative from battery to alternator
From Battery to starter

I am at work right now and cannot mentally recall any other connections. Obviously there is for the truck to draw power for all the other accessories. Any other exact locations I should check? I appreciate this guys

 

[SoNic67]

There is one more positive wire to the main fuse block.

 

[Afboy143]

ok so I went out today and got the alternator tested again along with the starter and solenoid. Everything tested fine. I also cleaned all surfaces with a wirebrush and put new connections on the ground wires to the chasis. The red top was at like 110 out of 700 CCA so they threw it on the charger. The new battery is in the truck- it's not doing anything. Do batteries come fully charged from the store aka wal mart? See the video below. This is with the new battery from walmart rated at 700 CCA hooked up and jump-wired to my mustang. Prior to hooking it up, the truck just clicks like a machine gun. When I hook it to the mustang, it tries it's hardest to start and won't. It turns over slowly once or twice then stops. The idle goes low on the mustang so you know the truck is trying to start. Take a look

 

[ponch68]

Sounds like you do have resistance/corrosion in the cables as mentioned befoere. Try cutting/pealing back the insulation on your cables to see if you find the greenish corrosion. I'd bet you have a bad cable or connection somewhere in line.

 

[OneLever]

I had corrosion in the battery cables where they connected to the starter on mine. Going to replace them completely soon. Dealership just crimped on a 4" wire with a butt splice and no heat shrink or electrical tape when they replaced the starter last winter during the snow storms. Didn't notice the piss poor job until later.

 

[Afboy143]

SO I FINALLY GOT IT! I took the battery I bought from wal mart to advance auto to get tested...it was a bad battery! What in the h*ll?! My optima was dying too since it wouldn't charge over 345 CCA. I bought a new battery from advance auto and BAM truck started up.

Moral of story: Don't always trust a brand new battery