Crazy headlight electrical issue.

[Dan Stuckey]

I bought a 184 about nine months ago. Really nice shape but the headlights were not working, in fact one was broken out. I purchased two bulbs for it, those being 4411‘s. So yesterday I pulled out the front and replace the two bulbs and wire them up. Turn on the switch at the Dash and get new lights.

So I will begin checking for voltage and ground and I could get close to 12 V on the wires leading to the bulbs. However even after running a ground from the battery with jumper cables, I could not get the bulbs to light. I took my auxiliary 12 V battery I use for testing stuff and hook that up to the bulbs and the bulbs lit up showing that they are fine. But for whatever reason hooking up the ground and the 12 V wire on the tractor, the headlights will not work. I tried all different things involving continuities of wires and the voltage, but just cannot seem to get these lights to work. I also discovered that I had 12 V to the bulbs even when the headlight switch was off leading me to believe that I’m going to have to replace the switch also. But how could these bulbs not be lighting if I have 12 V and a ground to them. This certainly has me scratching my head. I’m pretty decent with both DC and AC wiring but can’t figure this one out.

[Gary Dotson]

Are you seeing 12v. at the bulb with wires connected or is that while disconnected? If it’s when disconnected, it’s probably a bad switch supplying something continuity but not enough to carry the load with lights connected.

[Eugene]

I also discovered that I had 12 V to the bulbs even when the headlight switch was off.

Should be zero volts when switch is off. Indicates bad switch.

[Dan Stuckey]

Are you seeing 12v. at the bulb with wires connected or is that while disconnected? If it’s when disconnected, it’s probably a bad switch supplying something continuity but not enough to carry the load with lights connected.

Well guys, thanks. That certainly sounds like a good place to start. Ordering rt now.

[Larry B]

Probably 90% of electrical probs on tractors is corroded connections. Also remember there is a big difference between measuring voltage in a circuit flowing current and measuring voltage potential. Corroded connections that won't carry current can still show 12v on a meter as it has a very high impedance and does not load a circuit. Try using a 12v test light vs a meter and see what results you get.

[BullDAWG]

I agree with Larry though I don't have or use a test light. I check resistance (ohms). It should be low, the more rust, corrosion damaged wire etc. the higher the resistance the more likely the wires and or the bulb socket is bad. Try using fine sandpaper to clean contacts if they can be. I'm not sure if they are in a plastic piece or not. Sometimes they can be removed from the plastic piece. Usually has a clip that holds it in. Just use a knife or something like an icepick to pry it. But without pictures I can't be sure how or if this should work.

[Dan Stuckey]

Well here is an update to my headlight problem. I purchased a new switch from Hamilton Bob’s and install it but still no lights. With the dash out I could see that there were some of the speed connections that should’ve been cleaned up that might not even making good contact. So I did that and kept messing around checking some voltages here and there and was about to give up for the day. I had unhooked the eight pin connection beneath the dash to give me more room for the switch replacement. Thinking of the corrosion that could be inside the connection, I decided to give it a couple good sprays with electrical connection spray. I’ve never had too much faith in this stuff as you’re not actually scraping or touching the metal pieces, however I gave it a couple good sprays. Put the connection back together and wow, I had headlights. So I guess in my case, the problem was probably just connections all along. Incidentally I had tested the fuse holder independently and it was not showing continuity through it either. And the electrical connection spray corrected that issue. So now I have lights on my lowboy although I never even use it after dark. Thanks guys