'99 Century Class wiring diagrams

what's the last 6 of your vin?

 

Pablo, if you are doing wiring check the harnesses that go to the headlight modules. Where they cross from the frame to the hood is a real weak spot design wise. On my 2000 Century they slowly fray, and at some point I get really weird things going on with my lights and turn signals. The first time I went to rebuild the harnesses I discovered that they had been done before, maybe more than once.

Another issue I had was with the brake cans. Moisture had built up in the air lines due to a bad air dryer. Little rust spots had built up and were wearing the rubber diaphrams out. A little steel wool and elbow grease took care of that problem.

The shock and air spring under the rear of the cab next to the exhaust wear out every couple of years, due the heat and temp cycling.

This is probably just specific to a Cat engine, but the cab heater hose is routed sort of close to turbo charger, so unless you have some thing to protect or block the heat the hose gets baked badly by the heat and will fail. I use a larger hose slid over the smaller hose.

My tractor should hit 1.4 million miles some time next month.

 

I have an issue that I could use a wiring diagram. Century 1999, trailer marker lights not working.

 

I need lighting diagram (brake lights) for a 99 century, any help available?

 

I have problem with my lights blinking when my turn signal or hazards lights flash on. All lights are affected, marker, head, ####pit, on both sides. I had two mechanics try to fix it, because I've got a "fix it" ticket. The second one spend all day cleaning ground connections, charge me $ 600.00 yet lights behavior didn't improve a bit. I ran a wire directly from battery ground to one of the bulbs and nothing changed. I ran a wire from the battery + to a marker light and it stopped blinking. So for me the problem is either on the positive side
Still the mechanic insisted it is a ground issue, but I don't understand, because I am not a professional. It is always a bad ground and he's fixed many trucks with this problem. I don't know if I should trust my common sense or his expertise. I think I am right, but I can't fix it either. If I had a wiring diagram it could help, as would anyone with similar experience. I appreciative your time.

 

WOW, there are alot of '99 Century's with lighting problems. Never fail to under-estimate a Freightliner wiring harness. When doing electrical work, don't assume the wires are good because the loom is still there. The loom is more often than not the offender (it chews wires up like you wouldn't believe). I know this isn't specific but let's face it, how specific can you be when diagnosing an electrical problem with 3 lines of complaint with no test readings at all.