Not charging with new alternator

Hi, I am new here (to Tacomas), and 9 out of 10 repairs I have completed myself on every vehicle I've owned. But this one has me puzzled because I am not familiar with all of the little details like sensors, and which circuits effect others. Anyway, back to my problem:
A freind of mine Borrowed my battery. When he brought it back he went and put it back into my truck and hooked it backup. Well ever since then my speedometer has stopped working the alternator will not charge the battery and I have replaced the alternator, the heating and air blowers do not Work . I drove for a good while on a battery when it was fully charged, so I'm not sure if the alternator is just putting out a weak current or not. But my main concern is why all these other things when out, and what possibly may he have done wrong To cause so much havoc. Is it possible? Or is it something else and just happened to go out right at the same time the battery was put in .Any help from any of you long time Tacoma owners or just anyone who is this ran into the same problem.
Thank you in advance!

 

There should be a main fuse in the fuse box under the hood. Its pretty good bet its blown.

 

This is not a Tacoma unique issue IMHO, but an electrical mystery.

The first step is to have the alternator and the battery both tested and replace if needed. Yes, alternators can be bad out of the box.

Once that's squared away, you have to address each issue individually. It's possible that during the removal/install of the battery someone shorted something, reversed polarity or even have created a ground issue with loose cables.

I'm not sure how the speedo issue would be related.

But the blower failure is a very common thing and could be coincidental. Some searches here will find threads on how to diagnose and repair that, it's pretty straight forward.

 

You don't say what you are driving. Is the "new" alternator: new, rebuilt, a junk yard find? I assume you got a new voltage regulator with the alternator? Most voltage regulators are internal to the alternator nowadays. The alternator should be putting out ~14 volts when running.

 

Thank you Clearwater Bill. I will try testing the Alternator in place today. Did I understand you crore toy when you mentioned the blower being common, do you mean common with battery shorts?

 

The blower issues are common regardless of issues with alternators. Its likely its coincidental.

 

Mish, Its an 08 pre runner with the 4 liter v6. I believe you're correct in saying the voltage regulator is built into the alternator. But there were no charging issues on the vehicle it was pulled from.

 

koditten, do you know of anything that would cause the Speedo to go out like that?

 

The 120 amp main Alt. fuse is still in full contact across the gap. seems ok.

 

Get the electrical squared up first, find the threads on the blower info and examine your parts to see what's up.

Then worry about the speedo.

EDIT

Comprehensive thread on the blower situation. https://www.tacomaworld.com/threads/fan-speed-switch-not-working.70275/

Again, verify alternator/battery performance and connections before rooting around with other stuff.

 

Electrical issues involving alternators will cause the speedometer to read poorly. If the Alt. is not grounding properly, you can have all sorts of electrical issues.

 

I'll bet your buddy hooked the battery up backwards. I'm sure he won't admit that he did. It's possible he fried a whole bunch of stuff. Start by testing all the fuses with a test light or voltmeter.

 

Im having the same exact problem with my Tacoma....Did you ever figure out what it was?

 

Never Saw any real world Voltage numbers .

Without them it is like driving blind

 

Check ALL your fuses .Working on a 05 rav 4 blew gauge fuse. Ac ,speedometer vss ,3 power windows not working . Be surprised how much circuits run off 1 fuse .