Community Forums

gt350ed · 11-15-2012, 09:44 AM

Quote:

Originally Posted by MRBB

Another thing to know about: I had a 1990 HR with the 454 motor and it had an Alt. that was a dual type and it was no longer made. Neither was the regulator. It took me a month to get an Alt. and regulator that would work. None of the newer units will work. If you run into this problem PM me and I'll try to help you out.

HOLY MOLY!! I guess I'd sure want to know THIS somehow before going thru the huge labor of pulling the alternator. BTW, I'm of the impression that this alternator has a built-in regulator. How would I know?

MattC · 11-15-2012, 09:57 AM

I might have one more quick test, but I'm not sure when Delco dropped the feature.

Look at the back face of the alternator.
Can you find a D-shaped hole that has a brass tab in it?
That is a testing feature that was standard for years. With your meter attached to the alternator output, the engine idling and screw driver in your hand, use the screw driver to ground the brass tab. (This was a recommended procedure.)
The volt meter should jump up to something much higher.
If it does not, you have an alternator problem.

Matt

gt350ed · 11-15-2012, 11:27 AM

Quote:

Originally Posted by MattC

I might have one more quick test, but I'm not sure when Delco dropped the feature.

Look at the back face of the alternator.
Can you find a D-shaped hole that has a brass tab in it?
That is a testing feature that was standard for years. With your meter attached to the alternator output, the engine idling and screw driver in your hand, use the screw driver to ground the brass tab. (This was a recommended procedure.)
The volt meter should jump up to something much higher.
If it does not, you have an alternator problem.

Matt

Thanks Matt! Among the other suggestions I have received here, I will take a look for the brass "D" and try a test.

gt350ed · 11-15-2012, 11:30 AM

At this point, in addition to following the suggestions provided here, I'm going to post some pics so that you folks can see what I'm seeing. This will take awhile because my motorhome is in storage nearby. I'll try to do this Saturday.

In the meantime, I want to let you folks know how much I appreciate your efforts to assist.

georgetown350 · 11-15-2012, 03:27 PM

Someone in a previous post mentioned a fuse. We have a fuse labeled alternator in our front left compartment and when it is blown the alternator will not charge......... definitely worth checking

grizzlyalf · 11-15-2012, 03:59 PM

Here is a link as to which terminals should have power. I assume your alternator looks like this one
Wiring a Delco (GM) Alternator

gt350ed · 11-15-2012, 07:53 PM

Quote:

Originally Posted by grizzlyalf

Here is a link as to which terminals should have power. I assume your alternator looks like this one
Wiring a Delco (GM) Alternator

Although I'm not positive (no pun intended), I'm sure it probably is the same as mine although it would need to be clocked around to the right. As I look at the back of the alternator from within the coach, with the engine cover removed, the #1 main battery wire lug is at the 1 or 2 o'clock position based on how it is mounted.

jofo777 · 11-15-2012, 08:07 PM

IMO it is very likely a bad alternator. The bright side is if you get a good rebuild it will be trouble free for years. By that I mean new bearings and diodes. If it has some years on it is is always prone to failure. Those small frame delcos work a lot of overtime in a motor home.

Joe

grizzlyalf · 11-15-2012, 08:19 PM

Clock position doesnt matter 4 spots available The big heavy red should be always hot One of the white plug wires should be hot and one only when you turn the key if they are reversed it will kill the battery

MRBB · 11-15-2012, 11:01 PM

Originally Posted by MRBB

Another thing to know about: I had a 1990 HR with the 454 motor and it had an Alt. that was a dual type and it was no longer made. Neither was the regulator. It took me a month to get an Alt. and regulator that would work. None of the newer units will work. If you run into this problem PM me and I'll try to help you out.

Quote:

Originally Posted by gt350ed

HOLY MOLY!! I guess I'd sure want to know THIS somehow before going thru the huge labor of pulling the alternator. BTW, I'm of the impression that this alternator has a built-in regulator. How would I know?

I'm gettin old and it was a few years ago but the Alt. and regulator name started with D but not Delco. It had a regulator on the front panel that plugged in. I wound up getting an ambulance alt. and regulator from the guy who designed the org. ones. A MAJOR pain. I just searched for the name but could not find it. I may be able to find it on one of my post if it still exists. Don't let anyone tell you you can replace it with a modern one if it's this brand because it won't work. It was built to charge your coach and chassis batteries separately and needs a different circuit. I'll see if I can find the info for you.

tomwalt · 11-16-2012, 07:10 AM

If you decide to get a rebuilt alternator, have the dealer 'bench test' it prior to you taking it home and installing it.
I received a rebuilt starter one time that worked, but drew way too much current. A Bench test found this, but I got to do the installation/replacement twice.
A Bench test is free for the asking and will verify the part works. This will be useful knowledge just in case there is a 2nd issue discovered after the new alternator is installed.

vsheetz · 11-16-2012, 10:56 AM

In this thread, unless I have overlooked it, I don't see where the OP has verified the exciter voltage is present. If no exitation to the field coil, no alternator output. Many a good GM alternator has been unnessisarily replaced, then to find the exciter wiring or fuse to be the problem.

gt350ed · 11-16-2012, 12:07 PM

Quote:

Originally Posted by vsheetz

In this thread, unless I have overlooked it, I don't see where the OP has verified the exciter voltage is present. If no exitation to the field coil, no alternator output. Many a good GM alternator has been unnessisarily replaced, then to find the exciter wiring or fuse to be the problem.

You guys have been amazing in offering advice and suggestions. As I mentioned earlier, the motorhome is in nearby storage which I won't have a chance to test, etc. until next week.

For clarification, is the exciter wire the MAIN heavy red wire coming off the back of the alternator? If so, I can tell you that with the key off, the engine off, and the battery connected, there was definitely voltage to this wire.

gt350ed · 11-16-2012, 12:11 PM

Quote:

Originally Posted by georgetown350

Someone in a previous post mentioned a fuse. We have a fuse labeled alternator in our front left compartment and when it is blown the alternator will not charge......... definitely worth checking

I will pursue a fuse in line. But, because my Bounder is not a HR, the location will likely not be the same. I plan to trace and draw a schematic of all battery and alternator related wires and, coupled with some photos, repost here for everyone's consideration.