The dimmer switch in my 1940 PT105 truck has gone bad and I have obtained a replacement thst looks pretty good but is not absolutely identical. The terminals are similar but, again, not identical. If I have done this right I have attached a photo, and I would welcome any suggestions as to how to attach the wires. Should I just attach them assuming that the new switch is configured the same as the old?
Thanks.
Iwould hook them up as they were , the longer terminal would be the main current in ,the other two are low and high beam
You may want to put crimp-on terminals on the ends of your wires that will fit underneath the screw terminals of your switch.
To check compatibility of new vs. old switch check current paths with Volt / Ohm meter, comparing both. If no meter on hands, You can use a lamp and a battery to do the same.
Grteetings! Go
The mounting holes are different as well as the wiring terminals. On the old switch two are tied together while on the new all three are separated. The new one looks like the one in my '37. I would continue looking for a closer replacement. Have you checked the parts places? Where did the new switch come from? What year? I will check my catalogs when I get to the shop this morning.
Good Luck
Before u give up completely on the old one, u might try spraying lots of electrical cleaner- fromNAPA- inside the old one and work it a bunch of times to clean the contacts inside and out. I went thru the same process u have had and finally got my old one to work. I presume u have checked the wiring and cleaned the headlite switch in the dash.
Quote from: John Hendricks on November 12, 2008, 11:03:22 AM
Before u give up completely on the old one, u might try spraying lots of electrical cleaner- fromNAPA- inside the old one and work it a bunch of times to clean the contacts inside and out.? I went thru the same process u have had and finally got my old one to work.? I presume u have checked the wiring and cleaned the headlite switch in the dash.
On a 6v system any measurable resistance in the head light circuit will dramatically reduce the brightness of the lights. I ran the calculations with 1 Ohms resistance with my 25 watt/bulb headlights and was amazed by how much it hurt. You could be losing up to 80% of your light. See: http://www.ply33.com/Repair/lights
So, if his new universal style switch will physically fit (I do see an extra mounting hole on it that looks like it might be the correct spacing), I would be inclined to use the new one.
if you decide not to use the new switch let me know what you want for it ,i'm convinced it is a simple job to wire it up and as for the holes it's easy to drill a new one
Thanks all for responses. I neglected to mention in my original post that the little bright brass spot on the old switch is where the 4th connector had broken off. The old switch had 4 wires attached to it, while the new only has 3 terminals The happy ending involved taking apart the old switch and riveting in place the broken-off terminal. It is back in place with all 4 wires hooked up - still don't know exactly what all the wires are - and everything works fine.