In my 2001 Limited I have a fog light bulb that has burnt out and I decided to upgrade the bulbs to HID with a 35 watt ballast. After installing one of them I tried it out and it did not come on. I checked the voltage at the connector for the lights and only have 4.3Vdc. I installed a new fog light relay in the engine bay thinking that might be a source of the low voltage but still the same results. The fog light that still works comes on and everything is fine with that one however, I still haven't checked the voltage on that side. Back to the side that has low voltage I put my voltmeter on the positive side at fog light and negative side directly on batter post while it is running I am getting 14.3Vdc. When I switch it to the negative at fog light direct to positive post on battery I also get the 4.3Vdc. Would this mean the black wire going to my fog light is faulty and needs to be replaced? Anyone with any help as to where I can also look and do would be appreciated. I should also say that I just recently upgraded to LED headlight bulbs but the fog light was burnt out well before that and I do have DRL lights on.
Low voltage at fog lights.
- Thread starter KS_Steve
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19963.4lsr5
New member
Bad connection on your ground or a bad connector crimp.
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
Just went through this with my '99 Limited.
What I found was that the stock wiring was a.) corroded, b.) way, way too light gauge for the application, and c.) absolutely not doing the job. The voltage drop from the battery to the bulb was nowhere near what you need to get full performance out of a 55-watt stock-style bulb.
Previous owner had installed HID headlights, which kept falling apart inside the modified OEM headlights. This led directly to my next decision, which was to consult with Wil at Susquehanna Motorsports, and commission a new light harness similar to the one built by Slee for the FZJ-80 Land Cruisers.
Cost me around $300.00 with all the correct wiring and a set of Hella driving lights. The difference between the HID and the now-stock bulbs properly powered is not all that great, and subjectively, I think my headlights are now better than the HID kludge that was in there when I bought the truck.
Toyota headlights are usually really dim because they use like 14-gauge wiring, the connectors corrode, and on top of that, they run through the dash for power. Using the relay-based setup from Susquehanna, you get direct connection over much heavier-gauge wiring to the headlights (and other lighting, should you choose...) from the battery/charging system. This takes the performance up to a level that's competitive with the HID retrofit systems, and it has the added advantage that you're DOT-proof if you ever get stopped.
I ran the same setup to my fog lights that I did with my headlights. Performance is considerably better than it was, and everything remains essentially stock.
Only issue I've had is that there are some odd behaviors with the driving lights and the new harness. Leave the dash switch for those on, and then turn on the fog lights? The driving lights will come on and stay on when you turn the truck off, despite the "automatic off" for the headlights. I haven't quite traced out why it's doing that, but with the driving lights being LED, it doesn't drain the battery all that much that you can't start the truck if you leave it for a bit. Overnight? Dunno... I'm sure you'd notice.
Again, fix the wiring issue and your stock setup will perform a whole lot better, and you likely won't want the HID setup nightmare. You're also DOT-proof...
What I found was that the stock wiring was a.) corroded, b.) way, way too light gauge for the application, and c.) absolutely not doing the job. The voltage drop from the battery to the bulb was nowhere near what you need to get full performance out of a 55-watt stock-style bulb.
Previous owner had installed HID headlights, which kept falling apart inside the modified OEM headlights. This led directly to my next decision, which was to consult with Wil at Susquehanna Motorsports, and commission a new light harness similar to the one built by Slee for the FZJ-80 Land Cruisers.
Cost me around $300.00 with all the correct wiring and a set of Hella driving lights. The difference between the HID and the now-stock bulbs properly powered is not all that great, and subjectively, I think my headlights are now better than the HID kludge that was in there when I bought the truck.
Toyota headlights are usually really dim because they use like 14-gauge wiring, the connectors corrode, and on top of that, they run through the dash for power. Using the relay-based setup from Susquehanna, you get direct connection over much heavier-gauge wiring to the headlights (and other lighting, should you choose...) from the battery/charging system. This takes the performance up to a level that's competitive with the HID retrofit systems, and it has the added advantage that you're DOT-proof if you ever get stopped.
I ran the same setup to my fog lights that I did with my headlights. Performance is considerably better than it was, and everything remains essentially stock.
Only issue I've had is that there are some odd behaviors with the driving lights and the new harness. Leave the dash switch for those on, and then turn on the fog lights? The driving lights will come on and stay on when you turn the truck off, despite the "automatic off" for the headlights. I haven't quite traced out why it's doing that, but with the driving lights being LED, it doesn't drain the battery all that much that you can't start the truck if you leave it for a bit. Overnight? Dunno... I'm sure you'd notice.
Again, fix the wiring issue and your stock setup will perform a whole lot better, and you likely won't want the HID setup nightmare. You're also DOT-proof...
Thunderbear
New member
I just went through this as well, but since one leg was reading correct voltage, I jumped it and ran power and ground to the other side. Since I replaced those garbage H3 OEM lights with Baja Designs S1s pulling maybe 3A, I'm not super worried about wire size.
Definitely an upgrade. It's weird having foglights brighter than your headlights, but that's only until the HID install this weekend.
Definitely an upgrade. It's weird having foglights brighter than your headlights, but that's only until the HID install this weekend.
