I'm going to hook this thing up finally. I vaugly remember relay vs. no-relay threads a while back, but couldn't find them.

Is a relay necessary? Can the Harlen switch handle the ground needed by the MAP (GM) switch?

 

From what I can gather, the most relaible method is to use a relay. Run the wires so the relay and the harlan switch are inside the cabin.

 

i don't use a relay with mine

 

No relay, but I know it's been recomended to use one. No problems with my VI except a bad vaccum canister.

 

No relay here...

 

And you no-relay guys are using a harlen?

 

yes

 

no relay and using harlan works everytime for me
have had it on for 3 months now.

 

use a relay. there is no reason not to.. it is a couple dollars, and if nothing else, better safe than sorry.

 

no relay.. using NOS switch



what safety? what the hell are you talking about

 

If you pass too much current through the Harlan switch you could burn out a circuit, hence it's safer to use a relay which limits the amount of current passing through it and the Harlan switch.

The reason people are getting away with not using a relay is because the vacuum solenoid has enough resistance built into it to keep the current at a safe level for the Harlan. If you tried to power something like a high wattage light bulb (for instance) directly from the Harlan, you'd fry it.

 

well i got a NOS switch

 

no relay here for over 6 months and my harlan/mevi works great. the harlan can handle the very small amount of ground needed for the map switch to work. it is not that fragile, sprint uses it for a nitrous solenoid and that is sure to put more current strain than a tiny map switch, just don't let it get wet.

 

i didn't say nitrous soleniod.. i said Nitrous RPM Switch