What's the real purpose of cab lights?
 

This might be stupid, but I don't see the point of having cab lights for anything other than looks. Even on big rigs. I mean, the driver doesn't need lights (which he can't see from inside) to know whether he can clear something. I really like the look of cab lights but do they serve any real purpose?

oncoming traffic mostly, and low flying aircraft. lol

I like them but its just another place for water to eventually leak.

If your ever on a old narrow blacktop at night and you see the cab lights (atleast where i live in Missouri) It means theres a trailer attached and possibly a wide load.

On dually trucks, and bigger (wider) is a DOT requirement.

http://fmvss108.tripod.com/

1. What EOD said...It's for oncoming traffic to know that a wide load is approaching.

2. EOD (Explosive Ordinance Disposal)? If so I'm an Admin on a Steeler forum and one of the members does the same, in fact his Username is EOD related...My best girl-friend in High school her Father was was in EOD, traveled all over the world doing it as a Civilian employee for the Gov gone months at a time.

Yup I am doing the very same thing now. Doing the gov work that is! Is he still working? if so pm his name chances are I know him its kind of a small work force so to say...lol

i was always told it was to indicate trailer that was being pulled was wider than the pickup.

If I remember correctly,
The 3 inside lights are ICC marker lights and the 2 outside lights are clearance lights these are on both the cab and across the rear.

Clearance lights are required on a vehicle if it is 8' wide. The DRW trucks must have them on the cab AND also on the rear of the vehicle because their alxe width is 8' wide.

Before they became a vehicle option on pickup trucks, trailer manufacturers put them on both the front and rear corners of trailers, some even put the gang-3 on the front but all had them on the rear.

More often than not, a 1-ton SRW pickup will come with them on the cab because is is 'assumed' that someone buying a 1-ton truck tows trailers that are 8' wide. Many trailer manufacturers stopped putting the gang-3 lights on the front of their trailers, cost-cutting manufacturing overhead, because the 1-ton trucks had the clearance lights up front. The law stipulates that the lights must be on the front and rear of vehicles/trailers 9' wide. So, the clearance lights on the cab and the clearance lights kind of accomodated the 8' wide package from front to rear of the combined vehicle/trailer. Jim Lane is correct - the 3 inside are ICC and the two outside are designated clearance. If you tow an 8' wide trailer that does not have front clearance lights, either install them on your trailer or install the two outside on your truck's cab. Then you will be legal according to DOT law.

I just chose to have them as stock equip on my truck that way I would not have to worry about the DOT no matter what combo of trailer I might be hauling and how it may/may not be lighted properly. The more you have in compliance the less you risk getting harassed.

CD

I thought cab lights were meant to let the water drain from the roof!

cab lights are intended for haulers.

mine give the guys at the detail shop something to wax around... other than that... they just look cool....

I figured on single wheel pickups those lights were designed to release drivers testostrone when being view by others!

Replace them with the new LED's like I did and they are even cooler.
Jim
https://www.dieseltruckresource.com/...d.php?t=100449