• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

brand new Bosch 130 amp alternator blew fuse and crapped out?


Eddo Rogue

Well-Known Member
Joined
May 18, 2020
Messages
4,166
City
Burbank,CA
Vehicle Year
1993
Engine
4.0 V6
Transmission
Manual
Total Lift
skyjacker front leveling kit
Tire Size
31-10.50R15
My credo
Crossed threads are tight threads.
So I upgraded my alternator to a 130amp Bosch unit I got from Rockauto.

Im driving along , and decided to kick on the ac...Noticed my amp gauge jumped down and back for a sec, but thought nothing of it.

Stopped for fuel, and started back up....hit the gas hard followed by hard braking to fight my way into the relentless traffic jam that is everywhere all the time.

Suddenly after this, my amp gauge drops to zero and battery light comes on.

Luckily I was not far from home and limped my way back. the 15amp fuse in the under hood relay box had blown out. (the far right of the 3 if you are looking at it from the driver side fender)

I replaced the fuse and put my old 95amp alternator back in....working fine now...

but what caused this?

I spun the brand new Bosch unit by hand and it seems fine, but makes a slight scraping noise as if the inner fan is hitting the case or something.

Any ideas happened? Or did I get a bum unit? What would blow out that 15amp fuse?

I want to run the 130amp for an electric fan and some lights.
 
I owned a bunch of VW's when I was young and dumb and worked on all sorts of European cars at my first job. I learned that if it says Bosch, it's going to be expensive to fix WHEN you fix it, not if.
 
I owned a bunch of VW's when I was young and dumb and worked on all sorts of European cars at my first job. I learned that if it says Bosch, it's going to be expensive to fix WHEN you fix it, not if.

Dang really? so its like the duralast of Europe? lol

I went w/ the Bosch thinking it was a brand name, not quite like snap on, but at least craftsman....

So your saying it is likely my bosch crapped out? Had maybe 12hrs drive time on it....

I will admit it might have gotten a little wet while I was pressure washing the underside of my front end, and while I was bleeding the cooling system (kinda splashed everywhere burping out the coolant).

What brand would you recommend?Im trying to good, not cheap.
 
I bought a Motorcraft reman. I've washed a pile of engines, that shouldn't hurt the alternator. You drive in the rain, right?
 
I bought a Motorcraft reman. I've washed a pile of engines, that shouldn't hurt the alternator. You drive in the rain, right?
Yes thats what I figured, driving in the rain is fine, they should be able to take a splash of coolant....Checked my local stores, I'll pass on the remanufactured duralast...gonna order a motorcraft online.
 
is AC delco any good?
 
Walt hating on my VW's again.

I've found Bosch stuff works well on VW's. That said... I would take the reman Bosch alternator you bought and send it back. Get a refund or another unit.

I replaced my alternator a few months back... it was a new unit. It's still on and working fine. My plan is to repair the original... then keep the new on for a spare. I don't remember the brand... but I bought it on Amazon and it was delivered the next day. It was also cheaper then buying local from the box stores.

As for the AC Delco.... it really doesn't matter what you buy now days... it's always a crap shoot.
 
Assuming alternator fuse blew?

So most likely problem is not the alternator, but can be
You may need to clean the terminals on the starter relay post with the Battery positive cable on it, this is where the alternators B+ wire connects and carries ALL the alternators output amps

B+ wire at alternator should be a Black/orange wire, this runs in the harness to the starter relay post BUT.......changes into a GREY wire because that grey wire is a Fusible Link

So disconnect positive battery cable then pull off the nut on starter relay with other end of battery cable on it and all the wires on that post
Find the grey wire and unwrap harness until you find where the Black/orange wire is spliced to this Grey fusible link
That splice may be corroded and will need to be redone, just cut the ends, strip them back, making sure wires are clean no white corrosion, then re-splice

Also clean all the other wire ends on that post then put them back on


What can happen, especially when you put on a higher rated alternator, is that if the Black/orange wire and grey wire don't have a good connection to that starter relay post, then the AMPS need to find another Path to that post, and thats thru that 15amp fuse..............and well, it blows

The 15 amp fuse is the voltage regulator's Monitor circuit, the yellow/white wire on alternators 3 wire connector
 
Last edited:
Walt hating on my VW's again.

I've found Bosch stuff works well on VW's. That said... I would take the reman Bosch alternator you bought and send it back. Get a refund or another unit.

I replaced my alternator a few months back... it was a new unit. It's still on and working fine. My plan is to repair the original... then keep the new on for a spare. I don't remember the brand... but I bought it on Amazon and it was delivered the next day. It was also cheaper then buying local from the box stores.

As for the AC Delco.... it really doesn't matter what you buy now days... it's always a crap shoot.
I thought so too...I never had bad luck w/ them and word associated Bosch w/ quality stuff

But it seems times have changed and it is all a crap shoot, or just crap.

Unfortunately its not a reman, I bought it brand new from rock auto.

On the bright side I can turn it in as my core for a new one and still keep my original 95amp that I put back in and is working fine.

A spare alternator sure can come in handy...
 
brand new chinesium junk.....
 
Assuming alternator fuse blew?

So most likely problem is not the alternator, but can be
You may need to clean the terminals on the starter relay post with the Battery positive cable on it, this is where the alternators B+ wire connects and carries ALL the alternators output amps

B+ wire at alternator should be a Black/orange wire, this runs in the harness to the starter relay post BUT.......changes into a GREY wire because that grey wire is a Fusible Link

So disconnect positive battery cable then pull off the nut on starter relay with other end of battery cable on it and all the wires on that post
Find the grey wire and unwrap harness until you find where the Black/orange wire is spliced to this Grey fusible link
That splice may be corroded and will need to be redone, just cut the ends, strip them back, making sure wires are clean no white corrosion, then re-splice

Also clean all the other wire ends on that post then put them back on


What can happen, especially when you put on a higher rated alternator, is that if the Black/orange wire and grey wire don't have a good connection to that starter relay post, then the AMPS need to find another Path to that post, and thats thru that 15amp fuse..............and well, it blows

The 15 amp fuse is the voltage regulator's Monitor circuit, the yellow/white wire on alternators 3 wire connector
The force is strong in you....or you have been snooping around my truck, because you are right, that's exactly what happened!

I cant believe all this time I never noticed...After reading this I went out and just looking from under the hood, one of the wires is twisted together not even etape on it! Im gonna crawl under soon as the truck cools down and clean all that up. Just got back from visiting my buddys fab shop, my cute but capable lil ranger looked putrid compared to the monsters in there.

I think the "big 3" wire upgrade will be necessary before I pursue any more electrical related upgrades...

Time to order wire...and stalk the postman again....
 
made in usa with chinesium parts.
 
I might go for a Denso unit if I can find one in 130amp...I think they are still made in Japan, which seems to be the opposite of made in China
 
yes....denso...real denso..very good.

real. real not always easy to distinguish.


my ranger has a diesel in it. i finally bought a powermaster starter for it after fighting starter builds and alternators for over a decade... doing all delco part rebuilds. but even powermaster stuff can contain chinesium garbage. turns out delco is chinesium.
 

Sponsored Ad


Sponsored Ad

TRS Events

Member & Vendor Upgrades

For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.

Recently Featured

Want to see your truck here? Share your photos and details in the forum.

Ranger Adventure Video

TRS Merchandise

Follow TRS On Instagram

TRS Sponsors


Sponsored Ad


Sponsored Ad


Amazon Deals

Sponsored Ad

Back
Top