Hot Start Relay

Feb 5, 2013
Hot Start Relay
  • Installing a Hot Start Relay

    What a difference and for peanuts! I only have to look at the ignition switch and it starts on the button just like my Beetle always has.

    So why pay more I recon its cost me about £5 in total if that and about an hour of my time.

    You will need:

    I made up the cables - didn't have ring connectors big enough to fit over the 13mm bolts so just soldered wire to washers.
    Soldered the connections on all the cables for extra security.
    I found a small plastic tub to put the relay in but anything such as an old vitamins bottle will do - as long as the relay will fit in. (You dont need a 40A one btw its just they are cheaper than the others so why not have a higher rated one anyway)

    Please follow the diagram below ,
    Unscrew the 13mm nut on the solenoid (which has the thick Battery fed Cable on it) and connect your new cable to it, (Terminal 30 on relay and solenoid).
    Pull off the original thin wire from the ignition, (Spade connector terminal 50) and plug that into (Terminal 85) on the relay.
    Now plug in a cable (terminal 87 to terminal 50 on Solenoid) this will be the replacement igition feed via the relay but with no voltage drop!
    I connected the Earth connection (terminal 86) to a suitable point I already had on the body (the Rock and roll bed bolts) but you can use the 17mm bolt on the starter if you want.

    Should the relay fail in the future all you need to do is unplug the thin original spade connector cable from Terminal 85 and back onto terminal 50 on the solenoid (removing the new wire from terminal 87 to 50) at £1.95 I purchased 2 relays to have one in the van as a standby spare.

    Here is the diagram fairly self explanitory.(I did'nt bother with the inline fuse)

    I then used cable ties to seal the lid on the box and fixed it to the body just above the heat exchanger pipes - there is a handy area to tie to.

    Here are the bits (I used an old ignition lead cover for the rubber bung it pushes the relay against the inside of the tub and stops it moving about) Dont forget to tie up the cables a bit to take any stress off them.




    One slight annoyance when I had finished I tried it and nothing!!! What !!! I was annoyed - was the battery dead? Did I wire it wrong? duff earth lead?? Nope after 20 mins of faffing I found the relay was duff! I put my spare on and it was spot on perfect start every time! I called Vehicle Wiring Products and explained the situation, they were great and without any fuss said they would send me out another one.
    So tip for the day - test it before you seal everything up - school boy mistake!
steveagain likes this.