How to fit a 12v Hard Hot Start Relay Kit
Mark shows us how to fit a 12v Hot Start Relay Kit.
(00:00) Welcome back to Just Kampers, in this video, I'm going to show you how to fit a hard start relay, also known as a hot start relay. This relay helps to protect the ignition switch, as these vehicles get older the ignition switches become a little bit more worn, the resistance increases on the electrical part in the back and we don't always get the full 12 volts back to the starter motor to engage the solenoid correctly, so we put this in line at the back and that helps to protect our switch when you find your classic VW is getting
(00:32) difficult to start. I.e. you turn the key and all you get is a click at the starter motor and the starter motor doesn't actually engage to start the engine. It's more than likely that it's the ignition switch itself not necessarily the starter motor that's at fault, obviously we would need to check everything first, the easiest way to do that is to use a voltmeter and actually measure our voltage at our starter motor from our ignition key, we should be supplying a full 12 volts to that, if we're not that's probably why, usually
(01:02) because as I said before the ignition switch becomes worn and the resistance increases, so this is our key switch here we would turn this switch and that would give us 12 volt supply right the way around directly to the starter motor to engage it as this becomes worn the resistance increases, we could only be delivering possibly nine volts to that starter motor solenoid and that won't actually allow the starter motor solenoid to engage correctly and let the starter motor do its work. So that's why we fit one of these
(01:33) hence the diagram so, this is our four-pin relay, our hard start relay or sometimes called hot start relay very, very easy to wire up. There are only four terminals. Although this looks quite complicated, it's actually very easy, so our relay here we have a terminal 30 a terminal 86 at 87 and an 85. Terminal 30 is the live feed from the battery now, we've taken that from our battery feed at the starter motor itself as you see I've done our battery, which is our main feed to our starter motor, and we've hooked into that and gone to terminal
(02:11) 30. terminal 86 is from our ignition key switch now this relay doesn't take a lot of load to switch so we won't be experiencing the problems we would if we went directly to the starter motor loss of voltage this key switch even though it's worn will still supply enough current to switch our relay 85 we take that directly to Earth that's normally to chassis somewhere nice little dub of grease on there just to protect it from the corrosion from the weather terminal 87 is our output from our relay which goes to our starter
(02:44) motor solenoid and it's a small lucar terminal on the solenoid and that will then trigger that starter motor and allow the vehicle to start so looking at our starter motor here this little red wire here that comes from our hard start relay this is from terminal 87 and that goes to our lucar terminal up here just there on our starter motor solenoid now this one here is the main battery feed so that's our yellow wire which goes to terminal 30 on our relay this wire here comes from our key switch and originally went to our
(03:21) terminal where our lucar terminal is up there on the starter motor solenoid this now goes to terminal 86 on our relay then lastly terminal 85 we just take to Earth that's our relay fitted and screwed to the chassis underneath we did a separate Earth as well a little dob of copper grease on there to prevent the corrosion taped up the wiring [Music] and tidied up all the way up to the starter motor if you are experiencing that intermittent clicking fault at the starter motor we just want to protect and prolong the life of your ignition
(03:55) switch then our hard start relay kit is definitely the way to go. For more how-to videos, follow us on YouTube, Facebook, Instagram or visit us at JustKampers.com. Thanks for watching.
