CIH 1660 worklights

Hope I haven't asked this before. I have all the lights on the combine working EXCEPT the last three lights on the "worklight" circuit.

1)lamps test good...all will light if powered.

2)connections on the three lights read no power on VOM.

3) Power connections on the three lights read no power when put to an independent ground.

4) When a hot lead is connected to VOM and then to the ground for the three light it does not read.

If you follow the above, there is clearly a break in both wires to these last three lights. They are inside the loom and not visible. Does anyone know if these last three lights are wired in line with the previous ones (so the break would be between the last working light and the non-working lights) or does the wire for the last three go further back (hopeless to find).

I would be able to fix all this if I was not running blind. I need a wiring schematic for the light circuit. I have not been able to find one on line or a service manual for that matter. Does anyone have a schematic?

I've never been far enough into the light wiring to answer your question. Is there no way to get your local dealer to provide you with a wiring schematic. Mine has copied the repair manual before to provide wiring schematics of the hydraulic controls before. If all else fails, see if you can purchase to repair manual or diagnostic manual on CD-ROM. It a lot cheaper than the printed version

Dave I think I mentioned this to you before. Did you try it with the engine running?

Going to call Aldermans in the AM. They should be able to give me an idea on the schematic. I have to drive right by the place to pick up the corn head tomorrow, weather permitting. I think this is something simple...maybe a fuse? Was looking at the fuse box and there does not seem to be a fuse for the work lights in there. Flashers yes. Is there maybe another fuse box that is not in the ops manual that would have the lights fuse in it?

Indeed you did! And yes, I had high hopes for that one but was not the problem. Should have put that in the post.

Don't think it is a fuse as you already have some of the lights working. There's only one simple fuse block in the cab. I think you were correct in your thinking that it's a broke wire. I would try testing for continuity the wires to help locate a break. One of those multimeters with the audible continuity buzzer would be helpful

I was not able to locate any other type of fuse, breaker, etc. Still confused as to which fuse does the lights though, as it does not appear to be listed on the fuse box cover or the manual. Seems like it must be fused? Waiting on a schematic from my dealer. I really need this to do the circuit testing. Without it I am just guessing as to whether or not I am on the right wire.

OK, I got a fax from the dealer with a schematic. The lights are divided into three groups. Headlight, work lights and flood lights. The lights up front, with the exception of the one headlight, are designated as "floodlights" and the last three are the ones that do not function. These last three are not wired in series with the previous lights above the windshield. They have their own power wire, per the schematic, which goes directly back to the electrical access area outside on the right hand side of the cab. Here they connect to the flood lamp relay. At this connection point they are joined by the power wire for the other floodlights SO this connection would obviously have power and it is somewhere in the circuit starting there and ending with the ground on these lamps where my circuit is broken. There is also a connector located in one of the cab pillars that could be bad. Tracing a wire thru the various channels of a 13 foot high combine amidst rat droppings and chaff is not an easy task. I think that if I can ID the correct wire and check all the connections, though, I will find my problem. All other electrical issues on the combine so far traced back to broken crimp on connections. FYI...I thought you would find this interesting.

If you're getting power to the relay, I would just run new wires from the relay to the lights. That would be quicker than trying to track down a break in the wire. Plus as old as that combine is, the insulation on the wires is probably cracking and brittle further complicating the process

Exposed wires can be dicey but really not so much. The wiring on the inside parts are all real good. I need to ID which relay it is and take some readings BUT, there is a connector just below the right rear cab post somewhere I have to find first. It is a week link in the line. The relay is a standard auto store part. If it looks rough I can replace it on spec. I'll let you know what happens. Cutting hay tomorrow most likely, picking up the header the next day, work Thursday and baling Friday. Gonna be a dry spell here before I can look at it again!

Say, did you run a separate, dedicated ground to the lights/relay? They may be grounding thru the cab frame, and over time, those ground paths disappear due to corrosion of the frame. I just got done with that on my forage harvesters.

When you powered the lights, were you only running the 12+ volts to them, and using the original grounds? Or were you running a new + and a new
-?

Just wondering.

I've been using the original wiring because it looks pretty good. Tracing wires and looking for bad connections, breaks, etc. I have found several and repaired them as I go. This last bit is a trial but now that I know the complete circuit it is only a matter of time. Ultimately, if I don't find it I will run a new wire outside the loom to replace the old.

In testing the lights that are still out I created a new ground using a screw from the wiper housing. Clean wire with a gator clip on the end. Tested it on a working circuit and it completes a ground. So, yes I am making an assumption that the ground is no good so that I can work with one wire at a time. Once I get a good power reading with my new ground I will check the old ground or replace it with the new wire.