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Forgot to disconnect neg terminal on battery, then alternator made spark sound after disconnecting ground.

5K views 10 replies 6 participants last post by  Hacker_man  
#1 · (Edited)
Now when the engine turns on there are no electricity in the cabin. There was a repetitive beeping sound, but it seems to no longer occur

When key is Acc position, open door warning, air bag and check engine light are displayed on cluster.

The alternator is brand new and was replaced last week. I had to remove it again because I wanted to change water pump I did not the time do so in previous project.

Prior to spark incident, I had a separate contiguous task (ie same day) of replacing all 4 engine mounts. Unfortunately the jacks seemed to give way or I did not lock the jack in place properly. Pressure was applied to a quarter+ inch (6mm) thick cable that leads to the firewall before the cabin. I assume this is the shift linkage. I am unable to shift gears on the automatic transmission.

I lowered the subframe and PS assembly by 3 or so inches to have better access to rear mount bolts and due to mistake od having steering wheel mismatched from the PS spline (ie off center).

Any assistance would be appreciated before I take it to shop. I apologize ahead of time if this post deems drowned out in too much exposition.

Car is a 2003 LE 4 door with 150 thousand miles.

Edit: I came across a thread on this forum by a user with a similar issue and responder mention 100A alternator fuse. I've attached a picture of what mine looks like.

Do big chain auto stores in America have these? Or would I have to order through the dealership/ebay?

Edit: I came across d 'Bussmann 100 Amp Male Fuse Link' from a Google search.


 

Attachments

#2 ·
You can purchase these from the auto parts store. Here’s the oem part number for the 100A fusable link relay.

90982-08246

The part description just lists as blue male relay. You’ll need to contact your local dealer or visit a online Toyota retailer to see if you can order it and is available for purchase.
 
#5 ·
Welcome to the bone-head club! It's not like every first step of every repair manual for every repair type says "remove the negative lead from the battery" for a reason, it's just we know better.

In my case the spark at the alternator resulted in a $55 fuse, 2 hours searching for the bolt dropped into the fender area behind a huge wiring bundle headed to the fuse box.

I pull the negative to change wiper blades now.
 
#6 ·
 
#7 ·
Question to OP:

Are you saying the spark/blown fuse happened just because you disconnected the ground side of the alternator without first disconnecting the neg. battery terminal? You didn't short out the positive alternator lead to cause the spark?

I'm having trouble understanding the blown fuse just because you interupted current flow to the alternator.
 
#8 ·
The positive terminal is bolted to the alternator. Since the battery is connected, the circuit is still live. Fuse shields from over current.

Always disconnect from battery and allow a few minutes for energy to leave the circuits.
 
#9 · (Edited)
I understand the circuit is still live but whether the current flow is interupted at the battery or at the alternator should not cause an over current condition.

Unless there is some kind of "Lenz's current flow (Ldi/dt)" effect going on.

I agree it's good practice to always remove neg. terminal from battery first but I don't understand the failure mechanism in this case.
 
#10 ·
I got sparks at the alternator too. The circuit shows the path from the alternator to positive terminal of battery. Unless a circuit opened when it was supposed to be closed. Thereby blowing the 100a fuse.