Join Date: Mar 2002
Location: Austin, TX, USA
Re: Headlight relays questions....
You can measure a head lamp with a digital volt meter on the 10 amp setting (switch dial and leads). I thought about how to do this the simplest and here is what I came up with.
Disconnect one head lamp so you don't overload your meter. Leave the other side connected. Pull the relay out of the socket. Insert the ammeter leads accross the load pins of the relay socket. But you've got to get it right. If you put your meter accross the coil circuit you'll pop the fuse in your meter.
Measure high and low beam on one side. Double the sum of L and H beam current measurements to compensate for the disconnected bulb. Then fudge it up a bit. I'm gonna guess about 15 amps total (7.5 amps per lamp). If I'm close, a 30 Amp breaker wouldn't be out of line. What's the factory fuse rating?
Be sure to put your meter leads back in the volt-ohm sockets to prevent an abscent minded surprise when you go to measuring voltage again.
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI