850 Sport Coupe Relay Position?

Discussion in 'Rear-Engine Fiats' started by Jeff Stich, Sep 9, 2019.

  1. Jeff Stich

    Jeff Stich True Classic

    Norco, CA
    850 Sport Coupe with alternator (1970-on in USA); with the alternator field relay mounted to the engine bay ceiling (to the right of the ignition coil), what is the position/orientation of the relay? With the wiring terminals (spades) pointing to the right (passenger) side, or to the left (driver) side?

    Also, can a Sipea T20-12 relay be replaced with a (more-common) T-5170? (they are near identical-looking except for the position of terminal 87). The T20-12 is rated at 20amps/12Volts, anyone know the Amp rating of the T-5170?
  2. dnudelman

    dnudelman Daily Driver

    Glendale AZ
    The is an x 1/9 in the local pick n pull. Any value in snagging this relay off the x 1/9 for future? Or have we figured out a modern substitute that still is in production?
  3. Jeff Stich

    Jeff Stich True Classic

    Norco, CA
    The only "value" would be for you to simply have it as a spare (they rarely die, but sometimes a rusty wire terminal will rip out if/when trying to pull a wire off). I have a few spare T-5170's already (& a few other #'s), but my early Euro car has a T20-12 on it, hence my question(s).

    More importantly, show/tell us: what is the position/orientation of this relay on your 850 Sport Coupe?
  4. kmead

    kmead Old enough to know better

    I have both relays in the engine bay next to the coil. My car came with a generator and without adding wiring there was no way for me to get the alternator light to work. On both of my relays the wiring terminals face towards the firewall.

    I don’t know the answer to your other questions.

    Mine worked fine for two decades but I made the mistake of jumping my wife’s car and haven’t been able to get the system to work properly since. I am changing to an alternator from a Panda which is internally regulated. It is posing other problems but is low on my list of activities to solve right now.
  5. Jeff Stich

    Jeff Stich True Classic

    Norco, CA
    After a bit of detective work on my car, I found that the original mounting position of the alternator field relay was with the wiring terminals facing towards the ignition coil (ie: to the left). Unfortunately, this won't work on my car due to the fact that I'm retro-fitting a Marelli Plex 201 EI ignition coil pack (same finned alloy housing/coil/etc. as used on 124 Spider 2000) in place of the original points-type coil & bracket. The finned alloy housing wants to sit right where the relay wiring is, & squishing the wires up against the side of the alloy housing would (eventually) not end well.

    I ended up rotating the alternator field relay 180° on its mount, so the terminals now face to the right, instead. Various wire routing methods were tried, until I finally found an acceptable routing solution where the Plex coil pack fits in place & no wires were pinched or stretched or rubbing on anything nearby. I still have a bit of repair work to do, as the engine bay wiring harness on this car is quite a mess (partial cuts/slices or burned/melted areas, loose or missing end terminals & some wires randomly cut short).

    Btw, I chose to stick with the Sipea T20-12 relay that was already on the car, even though one of the wire terminals is "iffy" (a little loose). At least until I find out if the T-5170 is a direct swap, or locate/buy a new T20-12. ;)

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