remote start constant 12v, combine or no?

This is another generic topic that I think may be beneficial to future viewers.. and a good topic for discussion. How do you guys tag your heavy gauge inputs. Do you connect the 2/3 inputs together between the source and the fuse or the fuse and the unit? I've personally done it both ways. I normally do it between the source and the fuse (essentally having 3 fuses) just out of habit but I prefer doing it between the fuse and the unit. I have never seen a unit pull anywhere near even just 30amps and have even done a few installs (just 1 or 2 as a "test" so to speak) on the Chryslers with the small gauge ignition switch 12v and replaced the fuse on the heavy gauge to a 7.5amp (as to not blow the factory 10amp) and it never had a problem. I'm sure that may have been "pushing the envelope" so to speak and I wouldn't recommend it, but it never gave me a problem. So what is the general concensus here? And has anyone ever done an actual amperage draw test to see just how much a typical starter draws during its normal functions (remote start, parking lights, locks, etc). I'd really be curious to know what the true "typical" draw is.Kenny

Owner / Technician

KKD Garage LLC

Albany, NY 12205

Older starter wires, 15-20 amps, newer vehicles with "stepped" (geared) starter motors about 10 amps.

Really, the older starter wires really draw 15-20amps??? Thats actually quite surprising since the wire at the ignition is only powering the starter relay and possibly the "actuator" (can't think of the actual name at the moment) that pushes the starter gear into flywheel. I wouldn't think that would really pull 15 amps since the relay I would think was 1amp max and I can't imagine the actuator portion drawing that much...Kenny

Owner / Technician

KKD Garage LLC

Albany, NY 12205

Sorry Kenny, my answer should have been "for vehicles without relays". Which just happens to include nearly all Euros except Jaguar. Most US and Japanese use relays, in that case quite right about 1.5amps to trigger the relay.

Wow, and I thought I knew cars.. lol. I have always been under the assumption that all cars use starter relays or solenoids..Kenny

Owner / Technician

KKD Garage LLC

Albany, NY 12205

Kenny all starter motors have solenoids, that's the part meshed with the flywheel.

Right but i always assumed that the ignition wires onignition all carsthe only drove the relay and actuator portion of the solenoid... and that it was always only a few amps at most.Kenny

Owner / Technician

KKD Garage LLC

Albany, NY 12205

Gotcha...it ain't the ignition, it's the STARTER wire. But in that case why with so few exceptions are they at least 2.5mm (10gauge?). You only need an 0.5, (20gauge) to trip a relay. And also second starter wires.

Most vehicles I've installed in don't require more than 20-30 amps for everything including A/C or heater running at max, so I will usually combine the 2 (or 3) constant 12v 30A inputs. There are exceptions to the rule of course, but for the most part I combine them. I have tested the current draw on the positive parking light wires on some vehicles and it's about 4-7 amps. I try not to feed into the small gauge 12v constant wires. I like to go to the battery or a main 12v feed coming into thru the firewall in the DKP.

More on this, the old Mks II and III Golf/Jettas had a relatively thin (black) ignition lead, this was because it went about 18" max to the fuse box where relays took up the load.