Forum Discussion

Geocritter's avatar
Geocritter
Explorer
Dec 23, 2013

Don't know this electrical part, what is it?

I'm about to start work determining why my starter on my 1994 Holiday Rambler with the 460 V8 is giving me trouble (FWIW it's a new starter). Pictured here is a prehistoric circuit board located on the firewall above my battery. The big switch and knob is for isolating the battery. My question is, what is the item with the two cables going to it that I have circled in red, my guess is that it's some kind of fusible link but before I bypass it or jump it out while trying to determine what's not allowing adequate power to go to my starter I'd like to know what it is.

Thanks in advance for any help identifying the item.

Steve
Class A
  • Matt_Colie's avatar
    Matt_Colie
    Explorer II
    Dec 23, 2013
    Steve,

    Does it have 1 or 2 small wires going to other terminals - too?

    I don't have an HR. It looks to me like it is a contactor (Big word for relay) that maybe isolates the starting power.

    I can also tell you that no matter what, it the terminals and cables could all be helped by cleaning.

    Matt
  • PaulJ2's avatar
    PaulJ2
    Explorer
    Dec 23, 2013
    Do the two large terminals have 12 volts on them all the time? If so it may be nothing but a terminal/tie point. If only one then it may be a relay.
  • bullydogs1's avatar
    bullydogs1
    Explorer
    Dec 23, 2013
    That looks like a relay which would tie the alternator to the house batteries to charge and vice versa with the emergency switch.
  • K_Charles's avatar
    K_Charles
    Explorer
    Dec 23, 2013
    It's a solenoid, when a small wire tells it to, it hooks to large wires togather
  • BrianinMichigan's avatar
    BrianinMichigan
    Explorer
    Dec 23, 2013
    It may be a emergency start relay. It's hard to tell. It also looks like a connection terminal strip. pull it out, lets have a better look at it.
  • Altern's avatar
    Altern
    Explorer
    Dec 23, 2013
    Matt_Colie wrote:
    I can also tell you that no matter what, it the terminals and cables could all be helped by cleaning.
    Concur with Matt. ALL the terms need cleaning.
  • shooted's avatar
    shooted
    Explorer
    Dec 23, 2013
    Does the wiring diagram directly behind the component offer any clues?
  • John_Joey's avatar
    John_Joey
    Explorer
    Dec 23, 2013
    Wow, the first thing you want to do is attempt to find some Corrosion X and spray all that rust with it. That alone will save you future headaches. From that picture I'm guessing that rig sat out by the Texas Gulf coast for awhile.

    There isn't enough to see in your picture, but I think it's a good guess that it's the emergency start off the house batteries relay. That is a pretty stout wire going to it and it would carry a lot of current.
  • ScottG's avatar
    ScottG
    Nomad
    Dec 23, 2013
    It looks just like the relays Dodge used for its grid heaters.
    FWIW, I agree with the others that it's a mess in there. Your going to want to remove all the corrosion and probably just replace that buss bar. Otherwise your going to start having odd problems.

    Good luck,
    Scott
  • JimM68's avatar
    JimM68
    Explorer
    Dec 23, 2013
    it doesn't look like any relay I've ever seen, but I do think it is one.

    Such things tend to corrod onthe inside too, and corrosion causes resistance which could then cause low voltage to your starter.

    My monoco had a problem with the "bypass" relay, it acted good, but would not pass any real current. opening it up, which did require drilling out rivots and replacing them with screws and bolts, made it work way better, including the ability to start the diesel when the chassis batteries were dead, while holding the boost switch.

About Motorhome Group

38,705 PostsLatest Activity: Jan 14, 2025