Legacy SD70ACE has dim front lights, bright rear lights - ideas?

Anyone?

My guess would be a possible pinched wire or perhaps a loose wire that's just creating a sneak path to cause a voltage drop to the front lights.  IMO, this is not something that will be fixed without opening it up.

Thank you GRJ. Is there a drawing showing body screw locations available?

@Raven87 posted:

Thank you GRJ. Is there a drawing showing body screw locations available?

Normally, they're in the manual, but not in this case.  Here's the link to parts, and at the bottom of the page, there's the user manual and a wiring diagram.  The diagram might be useful here.

From that wiring diagram, the common denominator seems to be the ground to the front headlight board.  The headlight and number boards come from two different power sources, if all of them are dim, that's where I'd be looking.

Are the ditch lights and ground lights full brightness?

@gunrunnerjohn posted:

Normally, they're in the manual, but not in this case.  Here's the link to parts, and at the bottom of the page, there's the user manual and a wiring diagram.  The diagram might be useful here.

From that wiring diagram, the common denominator seems to be the ground to the front headlight board.  The headlight and number boards come from two different power sources, if all of them are dim, that's where I'd be looking.

Are the ditch lights and ground lights full brightness?

Thank you for that! Perfect!
All the lights on the front are dim - the cab light, ditch lights, ground lights, number boards, and the headlights. The rear lights - when in reverse of course - are full brightness.  

If the engine was purchased used, could the previous owner have replaced the original rear warm white bulbs with cool white bulbs?

I suppose anything is possible, but the front lights have almost a yellow tint to them. I have an SD70Mac and its lights are bright white front and rear including the cab light.

And, given that the unit is supposed to have LED bulbs, front and rear I don’t think there’s any way there is anything other than a power supply or ground issue.

I don’t know how I missed this before, but I just noticed before I started taking the shell off that the headlights and cab lights stay on even when the trains NOT running. Very dim as before compared to my other units but on none the less.
So there has to be a short somewhere?

Most likely something wring in the wiring.

Also, the parts picture didn’t really point out the shell attaching screw positions? Here is the bottom of my locomotive.

Sounds like a pinched power wire with insulation break to somewhere on the frame that's drawing power away from the front lights, a cold solder joint, or they didn't crimp a wire connection properly. See if you can bypass the power wire with another wire and see if that makes a difference in brightness, if it does, then remove that wire and try bypassing one section at a time between connections to find where the issue is. If you can't find it because it's hidden, run the bypass wire over the power source connection to the lights power connection, if it works fine, go and cut out the original wire and tape off the cut ends. Good luck with it.

Thanks Gary. But I ran into an accessibility problem. I cannot even get the shell off. I removed the four visible screws on the front part of the unit and the one large one  at the rear. But even having done that I can’t even get the shell to pry loose in any fashion. I don’t want to force itt  much less break anything so I put the screws back in.

So I’m going to take it my local hobby shop tomorrow who is also a service center and see if they can get it apart.

Do any of those speaker cover screws hold the cab on?

@BobbyD posted:

Do any of those speaker cover screws hold the cab on?

I really don’t know. I wondered that too but did not loosen them..

I think there are two screws hidden by the rear truck as noted by the arrows.
But all the screws were loose in the front and I still could not even the shell to wiggle?

I believe at least two of the speaker screws will have to come out as well.  Typically, the washer-head screws are the ones that hold the shell on.