Installed new directional switch on '65 series I FHC and right side works fully however on the left side nothing works. Bulb is ok and wiring appears in tact. I"m asking if there is a way to check this out.
Thomas:
Start with the basics…you’re confident that the bulb is okay and the wiring looks okay so that leaves the new switch as the prime suspect.
You’ll need to get a multi-meter if you don’t have one ($25 at Harbor Freight). You should also get a wiring diagram…readily available online from multiple sources.
Unhook the main connector to the switch. Using the wiring diagram figure out which wire provides 12 volts to the side that works and hook your voltmeter to it. It will show 12 volts when you flick the switch (obviously).
Now connect the meter to the correct colored wire that supplies the left side and flick the switch. Anything? If it shows 12 volts there’s nothing wrong with the switch…your problem is further downstream in the wiring or the bulb socket.
Are you 100% sure you have the correct bulb in there? Use the right side bulb in the left socket to make sure.
If the meter shows no voltage coming out of the switch on the left wire then your switch is faulty. If it’s new return it to the vendor.
Good luck!
Alan
N.J.
Alan thank you for the response. I do have a multi meter and wiring diagram. The switch has 8 wires that connect to the wiring harness. It is a new switch. I can see on the diagram a wire from each side of the switch that goes to a fuse. Are you saying that I should probe the connection of these wires with the multi meter to see if there is 12 volts with the switch on? Will check tomorrow. I appreciate your helping me with this. Tom. N.J.
Tom:
Yes…you mentioned that the left side doesn’t works so look at the wiring diagram and find the correctly colored wire coming out of the switch for the left side…it should be a red & green wire, I believe. See if that wire has 12 volts when you flick the turn signal switch (you may have to have ignition key turned on…I’m not sure).
Since the right side works the switch is obviously getting 12 v (through the red wire I believe). The problem is that it’s not sending 12 v out to the left side when you flick the switch…meaning the switch doesn’t work.
You might also try jumping the wires so that 12 v is being fed directly into the left side red-green wire…this should power the left side turn signals front and back to prove they work.
Don’t be too shocked to learn that a new switch is defective…the quality of reproduction parts these days is generally abysmal.
Carry on.
Alan
Thank you Alan I will try to test that today
Alan, I used the multimeter as you suggested and the right side that works is powered by a green white. wire out of the switch and shows 11.5-12 volts. When I tried the same on the left side that isn’t working I got 0-.005 reading. The left side is the green red wire as you said. So it appears that the switch is faulty and I’m about to call SNG Barratt where I purchased it. Thanks for guiding me through this exercise. I really appreciate your help. Tom
Thomas:
SNGB does a good job of standing behind their products…they shouldn’t give you a hard time (especially if you tell them you’re a member of this forum).
That being said, these switches are actually quite simple devices (no microchips or printed circuits). You can easily remove the black plastic plate (two screws) and fiddle with the brass springs and contacts to get it working again. But the easiest course of action is to get a new switch from the vendor.
Good luck,
Alan
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Alan, I spoke to SNGB and they listened to me but said they doubt the switch is bad because they never. heard of a bad one out of the box. They asked if I tried to jump the left side with the right side lead and I told them I tried but was unable to get it to work. They think it is something other than the switch but will take it back but have to send to England to have tested. I’m going to fool around with it some more tomorrow before I do anything else. Thanks for your input . Tom
I would suggest going to Youtube and watching this video along with others in the series.They go over the basics of electrical trouble shooting.
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