I have a 83 blazer diesel.Yesterday I couldn't get it to kick the starter.I had to jump it.I saw that it wasn't charging the battery.I replaced it with a new alt.IT did not do the trick.I'm at a loss to know what else it may be.:eek:

are all the grounds from the alt. good

are the bats new? what do the terminals look like? did you replace the belt when you installed the new alt? What kind of power is the alt putting out? put a tester probe on the nut on the back of the alt, then ground out the other prode. what kind of reading are you getting?

a loose or bad ground will give you all kinds of greif.

Get it running with a jump start, unhook the cables and confirm that you have 14 volts coming out of the new alternator. If the batteries are at twelve and the big nut on the back of the alternator is at 14, you probably fried a fusable link. If both are the same, suspect the batteries. Charge them up with an overnight charger, then unhook the charger and separate the batteries (unhook the + on one of them). Let them sit ten minutes and they should "float" fully charged at 12.3 to 12.5. If they don't , new bats are required. If they do, hook them back together and run the 2 hour headlights test. They should still be over 12.2 after two hours with headlights on. If they are, then start suspecting the starter.

I will give it a shot.Were would the fuseable links be?Also how would the starter be tested if it comes down to it?Thanks for the help!:D

i think on a 83 they are at the big battery lug on the starter and head up to the top of the engine. when you say it didn't do the trick what does that mean exactly . no charging? starter won't function? or just dead batteries?

Check the solenoid on the starter.Bad connection or if it's broken could be your problem.

What you really need to do is check all the grounds and then follow the wiring to the alternator. Start at the alternator and follow it back. If there are fusible links (sometimes there are, sometimes there aren't) you will find them and then you would need to test them.

It most likely has nothing to do with the starter itself (possibly the wiring to the starter depending on how it is setup - some trucks are different depending on previous owners etc.) because you were able to get it started with a jump.

Checking the schematic for the '83, there are three fusible links. Two are at the end of the wires that attach to the starter solenoid on the heavy lug that the battery cable goes to. The third is on the firewall - it is a diamond shaped molding with two threaded bolts (~1/8") and a metal tab between the two.

With a volt meter or a 12v test light, there should be 12v at:

1. the diamond molding terminals. This should be ok as you were able to crank the engine with the jump start.

2. the heavy wire attaching to the back of the alternator. this one should be ok too.

3. (unplug the two wire connector on the alternator) - the smaller red wire going to the alternator connector. No voltage here indicates a failed link.

Since you were able to jump start the motor, we assume the starter is ok.

With the batteries charged, there should be ~ 12.4 v across the battery terminals.

With the volt meter still across the battery as above, have someone turn the starter and see how much the voltage drops. It should be above 9.6 v while cranking. If not the batteries are probably bad.

Joel

Checking the schematic for the '83, there are three fusible links. Two are at the end of the wires that attach to the starter solenoid on the heavy lug that the battery cable goes to. The third is on the firewall - it is a diamond shaped molding with two threaded bolts (~1/8") and a metal tab between the two.

With a volt meter or a 12v test light, there should be 12v at:

1. the diamond molding terminals. This should be ok as you were able to crank the engine with the jump start.

2. the heavy wire attaching to the back of the alternator. this one should be ok too.

3. (unplug the two wire connector on the alternator) - the smaller red wire going to the alternator connector. No voltage here indicates a failed link.

Since you were able to jump start the motor, we assume the starter is ok.

With the batteries charged, there should be ~ 12.4 v across the battery terminals.

With the volt meter still across the battery as above, have someone turn the starter and see how much the voltage drops. It should be above 9.6 v while cranking. If not the batteries are probably bad.

Joel
Thanks .This is going to help a lot.Gives me places to check and not just probing everything:eek: to get a reading.Good to know were the fuseable links are.I will get to it in a few days and post what I find.

I got it figured out.A wire that goes to the fuse link on the firewall was repaired badly and gave out.fixed now and thanks for the help.I knew were to look with your help

Glad you got it fixed.