How to replace alternator in 99 Tahoe?

Hi!

The alternator won't be that hard to remove, but if you are not familiar with the process the assistance of a friend who has some more knowledge may be wise.

You can remove or loosen the serpentine belt at the point of the tensioner. This has always worked well for me and the belt is easy to put back on afterwards.

William

On my 98 sierra the tensionar arm is on the passenger side of the belt run, near the top of the engine, its a pully with nothing big attatched to it. On the fan side of the arm attatching it to the engine there is a 3/8" square opening, perfect sice for sliding a 3/8" ratchet or similar implement to get some leverage, give it a turn AND HOLD IT while you slip the belt off and then slowly release the tensioner back to its neutral position, don't let it slam. You may be able to just let the belt "hang" instead of removing it, or you may want to go ahead and replace the belt now and keep the old one as a spare depending on its age/condition. There should be a rough drawing of how the belt should be routed on a decal on the drivers side of the radiator housing if you do decide to remove it, it may fit more than one way, but will only work if properly routed (i know i don't want to put it the wrong way and have it turn a pully backwards!!) After that the alternator isn't all that bad, bolts and a few wires to play with.

I'm hardly a mechanic. I try to do what I can on my truck but outsource the big/difficult jobs, and oil changes. I decided to take a crack at the alternator when mine died.

Here's a list of the steps I took:

Remove upper radiator shroud (makes it easier to get the belt over the fan)

Remove belt, I bought a 1/2" breaker bar for this. on my truck I put the socket on the bolt on the pulley and pulled CCW, yours may be different (I have a 94 S-15 Jimmy with 4.3)

I totally removed the belt, after making a sketch of how it was routed. I took the opportunity to replace the belt, as another poster suggested.

Disconnect the battery, better safe than sorry, I took both terminals right off.

Remove red cable from back of alternator, there's a boot covering the connection, and a nut you have to remove to get the wire off

Remove bolts from alternator, I think there were 2 on mine as well.

there's a 4-prong connector on the bottom, this needs to be disconnected, easier to do once you lift it up, then the alternator is free.

Istallation is the reverse

all in all, the job took me, an inexperiemced person in repairs like this, about 45 mins, MAX. Then I went back to the parts store and got my $64 back (core charge, $60 plus tax).

I checked the belt periodically for the next couple days, just to make sure all was cool...

I would go ahead and change the belt even if you don't have to. Take the old belt and the tool of choice to change it under the front seat. This way if the belt blows in the middle of the night on some back country road you can fix it. It happen to me and luckily I had one under my seat with old ratchet and cheater pipe. Then when the store open and money allowed I pick up a new one put it on and put the old one back under the seat.

And if your radio says "Theftloc" on the faceplate, you better make damn sure you know the un-lock code or you'll be paying a GM dealership to get your tunes back.

Isn't there a 9 volt powered adaptor to prevent this problem when changing batteries and/or alternators?

Never tried one, but I remember something like it mentioned in tool catalogs.

I didn't think of that since I have a Sony deck in a vehicle that didn't even come with a "Theftloc" HU in the first place. The biggest PITA was getting the radio set up again...

That; or what I do is grab my spare battery for my Makita cordless drill and a couple of jumper wires and connect to the main power lug near the relay center.

Hi!

Or better yet--use that GM "radio" as a bookend after such an episode if you are unlucky enough to lock it up and not have the code.

The price the dealership may ask could get you a rather nice radio, especially if it's secondhand.

William

There is a belt tensioner when you remove the belt just lay it too the side or most of the time there is a diagram you can follow with belt placement.And yes there are only 2 bolts and 2 conncetions to the alt 1 is a snap in ele connector and the other is helt on with a nut .