I don't know what else to do...alternator not charging

I am completely flummoxed. :?

It all started with the amp light coming on. I had just replaced the battery as it was dead. So I started troubleshooting per the factory service manual. Problem: diode not working in the alternator so I replaced the alternator with a reman'd Remy 20170 (linky). Light went out on warm up, but then came on again.

Checked the alternator, it's generating an output with the Voltage Regulator -VR- disconnected and the field to output shunted. So that means the VR is not working. Ordered a new VR (Standard VR114). Installed per the instructions. Light still on and no output from the alternator.

Checked all the wires and connections in the starting/charging circuit. Replaced most connectors if there was even a hint of corrosion. Replaced a few wires just 'cause. Confirmed all have good continuity and everything is properly grounded. Still no joy.

Assumed the VR was a failed unit so returned and installed a new one. You guessed it -- still no charging and light is on!

My Jeep:
1970 Kaiser CJ-5, V-6 Dauntless
I'm second owner, first owner did replace the wiring but that was 20 years ago. Everything else is original.

What else can I check / do?
I don't want to just swap more parts, as I've done lots of that already -- Battery, alternator, voltage regulator. Continues to start with a slight touch of the ignition switch.

Regards,
Tim

 

That 20170 is a Motorola Alt and not a Delco Remy. Are you connecting the alternator as per Motorola requirements? Show a pict of the back of your alternator with wiring connected.

 

Can you read this one?
12 o'clock = field (green w/ white trace)
3 = ground (black & black w/ white trace) nb: I've put a separate ground to a common lug on the firewall (black wire)
6 = power (red)
9 = aux (gray)



Regards,
Tim

 

I stand corrected on the manufacturer of this design type alternator. Delco Remy does build new alternators on this Motorola design! Anyways looking at your pic I see a tab next to the field wire that is bare. Some of these brush packs had an insulated ground and required a ground wire connected to it and some had that tab grounded by is mounting. Can't tell for sure from pic on this one. You did say you full fielded the alt and it was putting out OK, correct? Was you able to read about 14 plus volts above 1500 rpm?

 

Yes, full field tested. Started at 13+ volts then climbed to 15.5 volts after about 1 min.

No problem grounding that extra tab. It appears grounded via the bolts, but then again I didn't mess with it. Tech at Remy said it wasn't necessary, but if it works...

Thanks, will let you know tomorrow. I've got other obligations tonight (mowing lawn...)

Regards,
Tim

 

Well, no joy. I put a lead from the blade ground to post ground, which is of course grounded to a common lug that is grounded to the battery negative.

Still no charge, amp light remains on.

Regards,
Tim

 

now if this was me . I would change it out . and go with a Delco SI alternator . very simple to wire up no external voltage regulator

 

That's my solution of last resort. Unfortunately I'm concerned there is an underlying issue that if not corrected means any alternator/VR combination won't work.

This weekend I will attempt to completely isolate the charging circuit.

Regards,
Tim

 

On Fussy, my 68 Jeepster, I have 6 wires on the alternator! My diode plate looks different from your alternator. I have three terminals on it, which your alternator does not have appear to have. I took a picture and tried to sort the mess out for you......



I charge just fine, with an ever so slight flicker in the lights noticeable at low idle. Gives it nice character!

 

Hmm, that's something to try. Thanks much.

Regards,
Tim

 

Okay, I tried wiring the alternator as shown on Fussy, no joy. Readings the same, not charging, amp light still on.

Below is the original alternator, it worked until it failed a few weeks ago. This is how it was wired.


Below is the new alternator, and how I wired it. When I talked with the Remy technician, he agreed I had it wired properly. This is also wired per figure H-38 of the FSM.


I'm going to try this again, but without the amp light in the circuit, just for grins. I've tested the new alternator by isolating the VR and it does pass the output test. I'm on my third VR so can't believe that's the issue, but other than eliminating the alternator, which presumes the VR is failed, I'm stuck.

Regards,
Tim

 

On the plate that has the B+ output stud you will see a small stud with an insulator under the nut. Connect the wire for the indicator light on top of that nut and secure it with another nut. Do not remove the insulator. This terminal should be the output from the diode trio. Leave all the other wires connected as you have shown. Let us know how that works.

 

I don't know if this matters or not but there are 2 alternators listed for your Jeep, a 37 amp and 55 amp. You ordered the 37 amp unit per part number. The physical appearance of the unit you received is that of the 55 amp unit. Could there be an issue with the vr and this alternator. Are the 2 alternators compatability with the same vr. Walt would probably know.

 

I tried Walt's recommendation. No joy. Just before trying that I checked all connectors to ensure solid continuity. The ground to VR was questionable (it wasn't solid but was reading ok) so I removed the plastic insulators and wrapped in tape. It all worked but only for about 30 mins. Then the light came back on.

Since then I've gone through all the checks again, and used Walt's configuration. From the FSM:
*H-69 ignition diode test #1 -- key off, 0v measured from aux to ground at gray wire terminal;
*H-69 test #2 -- key on, engine running, 5v measured aux to ground; 12.5v across battery
NB: while FSM says it should be 15.4/14.4, I'm not seeing that at 1500 rpm; this was test that red 0/12.5v on the original alternator, which is why I replaced it.

*H-70 alternator output test -- VR disconnected, short from field to output, engine running; battery voltage steadily climbs from 13v to 16v, then I remove the short.

At this point the FSM says the VR is failed. Just to be sure, I also ran the other tests.

*H-73 Alternator field circuit test #1 -- key on, engine not running, 1v measured at aux terminal.

*H-73 test #2 -- key on, engine not running, 2.2A measured from field to output.

45es: according to the FSM the same VR is for both 37 and 55 amp alternators. Also, online there is no choice by alternator, just make/model and year.

Regards,
Tim

 

According to Walt, the white (lamp) wire connects to the right lug (5 o'clock) on the diode plate. The FSM indicates the new alternator is configured as a 55 amp, whereas the original is a 37; hence I wired it to match. The spec sheet says the new one is a 37 amp. It's wired per Walt's recommendation for now.

Regards,
Tim

 

Hi Glenn,

Thanks; actually my FSM says the same: jumper to the aux terminal. That measurement was 1.6v steady but the Remy tech stated that didn't do anything, the proper test of the alternator was to jumper to output. And when I do that, it behaves as expected.

If that's wrong (jumper to output) then obviously the alternator has an issue. Frankly, I'm not 100% sure what I'm testing anymore.

Regards,
Tim

 

It would appear that the VR is bad, because you are getting a charge out of the alternator in testing modes. Just for snicks and giggles, separate where you have the white (light) wire and gray together. Put one of the wires on the terminal that has the insulated stud (bottom right in your 2nd pic) next to the main output post (red wires). Fussy wouldn't charge right until I separated those wires for some not-mentioned-in-the-service-manual reason!?!:?

 

In your post #14

*H-69 test #2 you said 5v measured AUX to ground when running?
The AUX terminal is what powers the voltage regulator so it can properly signal the field circuit to tell the alternator how much to put out.
The aux terminal should be 1 to 2 volts above the B+ terminal voltage when running. That means if the battery voltage is regulating at 13.5 volts then the aux terminal should read 14-16 volts. The aux terminal and the small stud at 5 o'clock in your picture should be at or very near the same voltage when running.
When you full field the alternator you should measure both of these terminals for output. See what you get....

Just a FYI: Many times a parts house test guy doesn't understand the AUX purpose and won't test this terminal. They full field for high output and call it good. Be aware that on this type of alternator, a failed diode trio for the regulator will have no effect on the bench test output of the alternator unless the do the alternator and regulator combo with all wires connected.