Installing A Hard Start Relay

There are numerous reasons why you may want to install a hard start relay on your vintage VW. A hard start relay basically directs the electrical current from the battery, through the relay and to the starter motor instead of routing it through the ignition switch. This eliminates a path of approximately 15′ of wiring and potentially bad connections. Once installed, your ignition key simply activates the relay. You can pick up a 4 post, 12v relay at most automotive stores, Ebay or Amazon for around 5 dollars. I already had some 12 gauge wiring and terminals, so I only have about 5 dollars and 30 minutes invested in to this project. You can buy ready made kits, but they can be pretty expensive, up to 35 dollars. Mabel wasn’t exhibiting any symptoms that would justify the install of the hard start relay, but not knowing what the future may hold, I thought I’d go ahead and install one. You don’t have to be a electrical genius to install the relay, but it does help to have the right tools. It doesn’t require any cutting or splicing of the original wiring. Wiring will vary from year to year, so depending on the age of your VW, your install may differ just a bit, but for the most part, it’ll be the same. If you look at the first pic, you’ll see that I’ve labeled what connector goes where on the relay. Start by disconnecting the battery. Locate the wire that goes from the ignition switch to the starter solenoid. Unless your VW has had previous wiring changes, more than likely, it’ll be a larger red wire with a quick disconnect. This wire will go to pin 87 on the relay. Make up a jumper that will go from pin 85 to the ignition switch (quick disconnect). Next, you need to make up a ground wire that will go from pin 86 on the relay to ground. I grounded mine where I mounted it to the floor pan support. Now you’ll need to make up a cable that’ll go from the positive post on the battery to pin 30 on the relay. You can also run this from the B+ post on the voltage regulator if you don’t want to run it to the battery. Lastly, you’ll need to mount the relay. You can mount it just about anywhere that will ensure a good ground. I chose the floor pan support. Don’t forget to connect your ground wire to the relay.

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4 responses to “Installing A Hard Start Relay”

  1. Roger L Duncan Avatar
    Roger L Duncan

    I can not find instructions for installing a hard start relay on a 62 vw.
    6 volt
    Has no wires under seat for wiring.
    Can you provide any guidance?
    Roger Duncan

    1. John Boyd Avatar

      Let me see what I can come up with Roger.

  2. Roger L Duncan Avatar
    Roger L Duncan

    Hi John,
    Thank You

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