Forum Discussion

asifnq's avatar
asifnq
Explorer
May 26, 2014

1989 Pace Arrow Alternator Problem

Hi

My S10 Delco Remy alternator is no longer coming online. It is showing battery voltage, only. Following is what happened.
I recently bought the MH and the alternator worked but the interior lights would never work. So traced it all to both coach and chassis kill switch relays. chassis one was bad and coach one was dirty. Also on the isolator solenoid all the wires were going to only one post as shown in fig A.

What I did.

1- Couldn't find a replacement relay so made the chassis relay to stay closed all times.
2- Cleaned the Coach relay so it works now.
3-On Isolator Solenoid. Moved aux battery and a small red wire to the other side of the relay. Also replaced the relay as it wouldn't close when 12v applied to the coil.

Now following happens.

Internal lights work when coach kill relay activated.
Engine starts fine.
Shows only 12.5V on the batteries with engine running.
I checked the post on the back of alternator, it shows the same voltage as the battery.
Got the alternator out and tested. It tested fine on the bench.

Appreciate any help, kind of lost now, why the alternator not charging. It only has two connections to it, one for the battery and the other not sure to where.

Further to this
following is a link to two documents.
Document A is how i bought the MH and alternator worked.

Document B is to what I changed the wiring to. Notice the wires on isolator solenoid.

www.zsamedia.com/abc.pdf
Class A
  • usersmanual's avatar
    usersmanual
    Explorer
    Nov 18, 2016
    Dog Trainer wrote:
    It sounds like the alt is not being excited although if my memory is correct the si10 is self exciting. In the future if you replace the Alt. You can put on a cs130 and get 130 amp output. Just purchase the adapter and make sure you get a 12V wire that is fired by the ign. Switch it will connect to one side. Of the connector the other wire will be one that has 12 V continuously. If you are not outputting from the Alt. Check to make sure you have a wire that is feeding 12V continuously it should likely be the largest wire and it may be red.


    obviously he has 12V to the alternator and he clearly says
    ""I checked the post on the back of alternator, it shows the same voltage as the battery""
  • smartntalentd's avatar
    smartntalentd
    Explorer
    Nov 17, 2016
    I have a 1989 Pace Arrow, Class A motorhome. I had to jump it on a weekly basis. I took it to the shop and learned a very expensive lesson. I was told the alternator wasn't charging the battery. Under the refrigerator, there is a circuit breaker box and inside that box there are two fuses. My fuses had went bad which prevented my battery from charging. A package of 30 amp fuses, cost approximately $5.00. I was charged approximately $150.00. I was thankful that it wasn't a much bigger issue.

    However, I am experiencing the same problem again. This time it's not the fuses.

    Does this model RV have an alternator? If so where is it?

    I was told it would be next year before a mechanic could look at it, I don't want to wait that long.
  • asifnq's avatar
    asifnq
    Explorer
    May 28, 2014
    Thanks everyone for all your help, this is really a great forum. I changed the alternator and it fixed the problem. Have 14.2V on the main battery when engine running.
    Now the aux batteries are different story, still getting 12.45V on them, however I will continue on this in the next post.
  • PaulJ2's avatar
    PaulJ2
    Explorer
    May 27, 2014
    Delco 10SI alternators normally has three connections on it. A large wire for the output to the battery, a two wire connector stamped on the alternator with #1 and #2. 2 should have 12 volts all the time, 1 should have voltage when the key is on only. 2 is the external sense to the regulator for sampling the system voltage. It could also be sampled internally depending on the particular alternator system. If the shop checking the alternator used an external source on the #2 connection a broken internal connection inside the alternator would be missed.
  • asifnq's avatar
    asifnq
    Explorer
    May 27, 2014
    I must also add that before there were two 12V truck batteries installed, one for chassis and one for coach. I removed the one for coach and replaced with two 6V deep cycle batteries, connected in series as shown on page B in the following link.
    www.zsamedia.com/abc.pdf
  • APRSRVer's avatar
    APRSRVer
    Explorer
    May 27, 2014
    If alternator bench tested good, only other thing could be a bad ground. Maybe the alt. is mounted with bushings. Make sure the case has continuity with engine ground.
  • asifnq's avatar
    asifnq
    Explorer
    May 27, 2014
    Hi, thanks for the response, I checked the only other wire going to the alternator it is red with two black stripes. It gets battery voltage as soon as ignition comes on. This 12.5V stays on this wire that is connected to the alternator as long as the motor runs.
  • APRSRVer's avatar
    APRSRVer
    Explorer
    May 27, 2014
    Agreed that the alternator is not being excited. Delco alternators have a stud on the back. That is the high current output and connects to the battery, isolator or separator as the case may be. A two wire connector on the side will have one red wire that will have battery voltage with the ignition position. It powers the internal regulator and the alternator field. The other wire from the two wire connector is an indicator wire.
  • Dog_Trainer's avatar
    Dog_Trainer
    Explorer
    May 26, 2014
    It sounds like the alt is not being excited although if my memory is correct the si10 is self exciting. In the future if you replace the Alt. You can put on a cs130 and get 130 amp output. Just purchase the adapter and make sure you get a 12V wire that is fired by the ign. Switch it will connect to one side. Of the connector the other wire will be one that has 12 V continuously. If you are not outputting from the Alt. Check to make sure you have a wire that is feeding 12V continuously it should likely be the largest wire and it may be red.

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