RTH: Testing the altenator

[GeoRoss]

I think that I am becoming the queen of real time help drama this past week.

I am searching right now, but it is difficult on a hand held device and so I am asking for a little hand holding.

I noticed rolling into Durango after a 12 hour day that the in dash volt meter is a little lower than usual. Just a needle above the half-way hash mark. Much lower than usual. Well after doing the train and what not I go back to looking at it.

The battery tests out at 12.4V. I pull the terminals and they are clean. The negative terminal needs to be replaced (crack), but is tight.

I tested the voltage across the battery after starting the Cruiser. The volts are 12.04V. I test from the b terminal of the alternator to the negative battery post or either the turn signal light ground or the main ground that comes off the battery and that voltage is 11.8V. No bueno. Correct me if I am wrong, but testing from the B terminal means that the fusible links are not wonky. Testing from multiple grounds would show that it is not likely a grounding issue though I will go and clean those up in a bit.

The belts are tight, about 1cm of deflection at the center. Here are some potential hints at problems. I recently had the engine bay cleaned with hot water to make changing out the leaking valve cover gasket less nasty. I started to notice the in dash voltage meter slightly defecting when the turn signals are on. Searching showed others with a similar phenomenon, but no other issues or fixes.

I guess I could go to Autozone and see if I can get the alternator checked in the vehicle.

Any suggestions or threads to look at would be greatly appreciated.

Thanks.

 

[GeoRoss]

No love cleaning all the grounds. In my haste I forgot to disconnect the positive battery terminal when pulling the B post of the alternator to clean it. Lots of sparks.

I guess the next step is to replace the main ground and get the alternator tested. I'm glad this happened in civilization rather than the middle of BFE.

 

[alia176]

Ross,

Are you able to take it to an Autozone type place to see if the ALT checks out? Sounds like it's not putting out 14 volts to recharge the battery.

Couple of easy things to check out:

- If the engine has been running for 15 min or so, what's the voltage at the ALT Batt terminal (at the alternator)? May need to peel the rubber boot back and do a test.

- shut the engine off and see if this post "feels" super hot. Also see if this connection is tight. I think it's a 10mm socket if memory serves me correctly after having some Vodka tonics....

- check the 7.5 amp CHARGE fuse at the fuse block under the hood, pass side.

- also check the 7.5 amp IGN fuse located in the inside vehicle fuse block.

Report back. PM me your phone # if you still need help.

Ali

 

[IdahoDoug]

Yep, 10mm having changed out an alternator last week. Ali's got good advice to which I'd add pull the square connector off the back of the alternator and blow it out with either compressed air or a can of compressed air such as used cleaning computers. Blow out the alternator side of the connection also. If the engine's hot and you have time, just leave this connector hanging with the hood up and the heat and convection will further dry it.

With water in the equation, don't get too hasty about replacing anything until the truck's had some time to dry various connectors that may have gotten wet.

DougM

 

[GeoRoss]

Thanks for the suggestions, I'll check those fuses in the AM. The engine bay cleaning was three weeks ago so my only concern with that is developing corrosion. I cleaned all the grounds and checked all alternator plugs. B post nut was very tight and clean.

I will be replacing the main battery ground as the little crack in the terminal is now terminal. My futzing with it has almost fully broken it. Once I get the hotel deal dealt with I will run by and get the alternator checked and replace that ground. I wish I had a place to do it as getting to that engine block ground would be easier with the tire removed.

I'll post up results in the AM, thanks again for the ideas. The wimmen folk may go rafting tomorrow while I sort this out.

 

[GeoRoss]

Well, I checked the IGN and CHARGE fuses. They were good by visual examination. Drove to the Autozone to have the alternator checked. He didn't want to do it while still in the truck and wanted me to pull it. I'm on vacation! I had made a contingency plan to go to the dealership for diagnostics for some moolah. As the noon deadline for overnight parts loomed I called American Toyota and Antonio helped me out. He helped me find a cheaper way to get it here too. Thanks Antonio. I did this as a back up. The dealership called an hour later telling me the alternator is no good. I don't know specifically what was no good yet. The local service writer then began to apologize that he was not going to be able to get the part in till Friday AM. I told I had one coming in tomorrow from ABQ. I'm going to let them install it and that way I can go white water rafting with the family and not wrenching in a parking lot.

I'll post up what part of the diagnostics it failed out when I find out.

Thanks!

 

[CJF]

I'll post up what part of the diagnostics it failed out when I find out.

I doubt they'll have more info than, "We put it on our tester and it failed."

Stuff like that sucks when you're on the road; glad you got it dealt with.

Have fun rafting!

Curtis

 

[IdahoDoug]

Yeah, it will just be "failed". Hope rafting works out and bummer it happened on the road. Nice to have help from American Toyota, however.

DougM

 

[GeoRoss]

Out of curiosity does anyone know what the shop rate time on replacing an alternator is? I am afraid that someone may be trying gouge me saying they've been working for 4.5 hrs and still not done. I think I've done it with someone else's 80 in under two hours.

 

[GeoRoss]

Well, you guys were right, the tech justed tested the voltage across the battery and what I did to diagnose. He says that he noticed some of the wiring was chaffed coming into the battery. Not the ones that were part of the Main/AM1 lines but the other one. Spliced in a new section. I had a new set of belts put on as a while we are in there.

Well all should be good right? I head to the grocery store get some ice from the dealership I notice a burning smell. That is no bueno. I stop and get the hood open and there is a faint smell. The belts seem a bit tight, no rubbing. I am worried about a seized AC compressor. I can't turn it by hand while the engine is off. I start the engine and no slipping or further smell with the AC on or off. Hmmm. I notice a piece of electrical tape that seals the insulated pipe that runs along the PS of the engine. I wrap that up hoping that was the problem.

I get my ice and head back to the hotel. Start it and get the Christmas Tree of Death for no charging. Hmmmmmm. When a fusible link dies, is there a burning smell? I'm now entering a world of no fun. I'm going to go check the alternator again with the volt meter by checking across the battery posts and from the B post to body ground. That will isolate a wiring issue/blown fusible link between the alternator and battery correct?

By the way, rafting was a ton of fun.

 

[GeoRoss]

Well, the car runs, head lights turn on, wipers, antenna motor, horn, etc show that the fusible links are ok. The fuses for CHARGE and IGN have 0.0 on the Ohm and are good.

I still have 12.4V across the battery (Orbital Exide), but when running I have 12V across the battery and 12V from the alternator B post and the neg battery and body grounds.

It was charging by the in-dash gauge when I left the dealership and not after I shut it down after smelling the burning smell.

My two guesses are that either the tech did something bad electrically or it was a bad alternator from Toyota. I hope that anything bad the tech did with wiring did not kill the new alternator.

There are four wires coming into the positive battery, one is in a loom and large. Two of the go into the Main/AM1 fusible link. The last one is what the tech spliced on.

Time to take the troops to dinner.

 

[retrofive]

Is the 3 wire fusible link.... meaning he spliced into the AM2 fusible link wire in the loom? WAG

 

[OGBeno]

Well, the car runs, head lights turn on, wipers, antenna motor, horn, etc show that the fusible links are ok. The fuses for CHARGE and IGN have 0.0 on the Ohm and are good.

I still have 12.4V across the battery (Orbital Exide), but when running I have 12V across the battery and 12V from the alternator B post and the neg battery and body grounds.

It was charging by the in-dash gauge when I left the dealership and not after I shut it down after smelling the burning smell.

My two guesses are that either the tech did something bad electrically or it was a bad alternator from Toyota. I hope that anything bad the tech did with wiring did not kill the new alternator.

There are four wires coming into the positive battery, one is in a loom and large. Two of the go into the Main/AM1 fusible link. The last one is what the tech spliced on.

Time to take the troops to dinner.

So where exactly are you guys Ross? Are you close to ABQ? If so, dude, we need some beer time to look over the issues.

 

[GeoRoss]

So where exactly are you guys Ross? Are you close to ABQ? If so, dude, we need some beer time to look over the issues.

We are in Durango CO right now. I'm not sure we could make it to ABQ with only the battery and no charge. Beleive me the thought has crossed my mind to have access to a well stocked parts department.

 

[OGBeno]

We are in Durango CO right now. I'm not sure we could make it to ABQ with only the battery and no charge. Beleive me the thought has crossed my mind to have access to a well stocked parts department.

If you keep the truck running, you can make it to ABQ.

Let me know when you are here.

 

[CJF]

Spliced in a new section.

Oh dear...

 

[GeoRoss]

Well, if memory is correct Main/AM1 fusible links go from the battery to the black plastic box. AM2, the one with the gray connector goes from the battery to a split. I think the tech spliced out the AM2 fusible link.

Could this have caused the current failure? The following two pictures are of this area. There are the main harness and the Main/AM1 fusible links. The small red wire is for the CB and the large red wire is the splice. The second photo shows where it is spliced into.

The third photo shows what we were doing while the wiring shenanigans were going on.

Can someone please confirm that this fusible link was spliced out. Will this require a new wiring harness? How screwed am I?

Thanks,

 

[retrofive]

Ill take a closer look at mine in the daylight and report back.

 

[medtro]

Can someone please confirm that this fusible link was spliced out. Will this require a new wiring harness? How screwed am I?

Yes, he replaced the fusible link with gray connector with that thick red wire. Wonder why he did that?

If you want to go back to use stock fusible links, you will need to source the gray connector on the harness side.

 

[GeoRoss]

Well, the tech is pretty clear he didn't cut anything out. I did recently have the AC serviced and the engine bay cleaned. It is possible that one of them messed something up and cut out the AM2 fusible link. The tech says he only cleaned up that fubar.

I have a set of fusible links and we'll just clip and soder AM2 back in. All the wires have continuity. So I guess it is possible that it was a bad alternator as it is getting 12V at the B terminal. Sadly it looks like I will be replacing this portion of the wiring harness. Could there have been a short in the charging sensing circuit? Any help or ideas would be greatly appreciated.

IIRC this is part of the main engine wiring harness and mucho dinero. Can someone confirm this?

Thanks