Alternator?

[fyton2v]

The battery light is on in my 100. It's still starts fine, but my wife just mentioned that the radio was cutting out (powering off) while driving.

Do I need a new alternator? I'm at about 100K miles. How difficult is it to replace?

Thanks.

Oh. My wife just called. I had her leave the brights on for a few about 15 minutes while the 100 sat to put some stress on the battery. Now it won't turn over. I had some trouble like this about a year back (the battery is about 9 mos old) where the truck would run fine, but just not start the next day. Checked the voltage and it seemed like the battery wasn't holding a charge. Replaced the battery and I've been good for 9 months.

This time I bet I'll see a lower voltage reading going to the battery.

 

[LXRunner]

The battery light and radio mailfunction are both indicate that voltage is too low.
It is not difficult to replace alternator, but first check following:
1. connector on alternator plugged properly, no wires apart of it.
2. Serpantine belt tension OK and it does not sleep on alt. pulley.
3. Battery (how old is it?) have good connection.

In some cases old batterys may affect voltage badly.

 

[spressomon]

Yes...be sure to check the battery connections...and maybe more than check them: Clean them thoroughly.

Then if the battery still won't keep a charge have the battery load tested.

If the battery checks out then the alternator might well be your culprit. Although I don't recall anyone having to replace an alternator...or certainly it's not like the starters needing to be replaced/rebuilt at 100K.

 

[maingear]

The alternator should produce 14 Volts DC. Battery (with engine off) should have 12 Volts.

Does your positive battery terminal have an ALT (alternator) fuse? Can you pull it to check for corrosion?

Sounds like your battery life may be related to a slow drain or weak charging (poor wire connections).

If you do find that it is your alternator, and you are capable of removing it yourself, the diodes are easily replaced.

Accessing the alternator is the hardest part of changing it. Access may require removal of a skid plate and fender liner. Take it to a parts store for a free test.. Most have special machines just for checking them.

 

[LEXUSBEN]

Batt light on usually means alt circuit, could be the battery if it is really sulfated and won't accept any charge, usually gets gradually worse, not an overnight instant thing.

Down and dirty fastest way to know if its the alternator.

Key on, engine off

make sure you have batt voltage (12v) at the main terminal (big wire) and the 3 terminals in the connector on the back (unplug when checking). This test works for pretty much any toyota.

If you pass this test problem is most likely internal to alternator. I would guess
brushes, since they are a wear item. How many miles?? If you suspect brushes
try tapping the alt with a hammer if you can get to it. Maybe use and extension and bang on that. Sometimes it will knock the brushes back into place and everything will work temporarily.

If you can find someone to do it I'd just replace the brushes, Parts are $25. Alternators are not cheap. I've done just brushes in numerous toyotas and they've gone another 100-120 k miles. Dealers usually want to replace the whole thing though.

I put some in a 62 I had a few years ago and everyone in the shop thought I was crazy. Crazy to the tune of $450 in parts savings alone

HTH

 

[fyton2v]

Here's the status:

Battery was dead when I came home. I jumped it. When running the voltage starts out at 11ish and starts dropping. When off it picks up where it left off and starts going back up to around 11ish. With the key on (no engine running) it drops too, which makes sense.

LEXUSBEN,
Not sure about your test. Could you be a little more descriptive? The connections on the other side of the terminal (the bolts connected just below the main and alternator fuse) have the same voltage drop.

Also, all terminals and connections look clean. I'm having a difficult time yanking the alt fuse. Should I just pull harder? I'm a bit afraid, because it doesn't want to come out.

 

[100 TD]

Check the following fuses, yes rip them out and check them

ALT-S 7.5 amp fuse near battery/fusible links
GAUGE 15 amp fuse, probably left kick panel
140 amp fusible link near battery (main wire from alternator to battery )

 

[fyton2v]

I literally can't yank out the 140A fuse. I actually cracked it already. Good times. I think it might help if I undo the bolts, but everything is clean. I doubt it's corroded. I live in SoCal. We don't corrode here .

This really sucks because we are (were) going to the mountains tomorrow morning. However, I found a place with an alternator. I think the main question I have is... Is this a job I can do myself in a matter of a few hours without an FSM? I have tools. It's tight in there. I've taken off the skid plate to get to get a better look. The alternator looks fine . The bastard should work!

Is there a place where I can test voltage leaving the alt without electrocuting myself? How the hell do I release and restore tension to the S-belt?

Damn it. Thanks guys.

 

[LXRunner]

Disconnect wire from terminal "B" of alternator. Start engine.
Check voltage between "B" and Ground. shouldbe 13.2 - 14.8 volt.
If reading is less than standard, remove alternator rear end cover and with terminal "F" grounded (use screwdriver to short it)'
start the engine.
Check voltage between "B" and Ground.
If reading still less then standard - BAD alternator.
(May be bad rectifier) But not tipical problem

 

[fyton2v]

I certainly don't know what I'm doing, but I'm not seeing a way to do any of this stuff without taking off the alternator. Very little room to maneuver in there. I can barely get my voltage meter wand in there to poke around... and where I do (which I think would be terminal B because there looks to be a wire heading towards the block) I don't get any voltage. I'm sure I'm not hitting the right spot. There would be something voltage coming from it... no?

Disconnect wire from terminal "B" of alternator. Start engine.
Check voltage between "B" and Ground. shouldbe 13.2 - 14.8 volt.
If reading is less than standard, remove alternator rear end cover and with terminal "F" grounded (use screwdriver to short it)'
start the engine.
Check voltage between "B" and Ground.
If reading still less then standard - BAD alternator.
(May be bad rectifier) But not tipical problem

 

[LEXUSBEN]

140a fuse is bolted in. Should be able to pop the clear cover off and visually inspect it. Only time it blows is if the car is jumped backwards

b+ terminal on alt - the one bolted on with a 10mm bolt, and the plastic connector on the back which should have three wires in it.

 

[LXRunner]

Yes, from "B" it is BLK wire goes to 140A fuse, then to "+" battery.
Another wire is WHT/BLU from alt. goes to 7.5A fuse (it's next to 140A fuse), then to "+" battery.
Next wire from alt. is RED/BLU goes to 15A fuse (Left kick panel), then to IG11 relay (on left fender panel) - you have to measure "+12 volt on it only when Ign. key "ON" or "START". It depends on 80A fuse (AM11) and 20A fuse (AM12) that locates close to relay.

 

[fyton2v]

One last thing I noticed. The "B" connection on the alternator has stuff connected, but there is another post "bolt" coming out of the bottom (near six o'clock) that has nothing connected. Seems odd. Normal?

 

[LXRunner]

I think it is terminal "F" (see my post #9). Actually it should be on "near six o'clock" , but under rear end cover.

 

[LXRunner]

And, sure, nowires on terminal "F".
BTW, one more wire is BLK/ORG goes to dash "CHARGE WARNING LIGHT"

 

[fyton2v]

Nah. It's not the F terminal. It's something else on the bottom. It's probably not used.... but....

Eff it. I couldn't get off the alternator because the power steering pulley is in the way. I thought it would drop down, but it slides out and off (if the power steering pulley weren't in the way). I can't get the pulley off.

I'm limping to a mechanic tomorrow morning to see if he can repair my pride and my Cruiser.

 

[Auggies'Blu]

Since "replacing alternator" is not in the FAQ list, can I assume its not something that needs to be done. Or at least not often enough!?

Can anybody who's done this please provide pictures of the work and/or location of the alternator? I know this sounds weak but I haven't had the opportunity or need, really to get into the engine bay of my rig. It doesn't help that I'm living in an apt complex where the local busybody calls the main office to complain that I'm performing work on my vehicle if I even lift the hood to check the oil!

Thanks guys!!

 

[fyton2v]

The trick for me was figuring out how to remove the power steering pulley. I couldn't do it.

A How To would be nice.

Thanks for all the help everyone.

 

[richg]

The trick for me was figuring out how to remove the power steering pulley. I couldn't do it.

A How To would be nice.

Thanks for all the help everyone.

I'm not in front of my truck right now, nor do I have my FSM handy, but there is likely some fancy special tool to hold the pulley in place while loosening/tightening. But I'm pretty certain I just used my impact gun when I did the timing belt. A strap wrench would probably work as well assuming the nut isn't silly tight.

rich

 

[fyton2v]

Follow-up after my trip.

The 140A fuse WAS blown (insert the "F" word). It really helps to know what you're looking for. You can't tell if the fuse is blown from the top so I missed it.

My mechanic replaced the fuse and installed a new alternator. Something blew the fuse, and since I recently had some bad times with battery life, swapping out the alternator can't hurt.

Live an learn.