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Im installing my new wiring harness and have a question. My circuit breakers have both a large and small douglas connector on them but I cant find a large connector to feed them. My ignition switch has small ones on it also.
Thanks,
Circuit breaker help
Moderators: Cal_Gary, T. Highway, Monkey Man, robi
Circuit breaker help
Gerry
53 M37
53 M37
Re: Circuit breaker help
I do not know about the question asked. How much faith do you have in the original circuit breakers? Should we be using them or going with modern fuses or breakers if safety is wanted over originality? I work as an electrician, and some old breakers are really switches at this point, which do not function in an overload or short circuit situation.
Re: Circuit breaker help
Hi Gerry,
Looking at a wiring diagram for the M in TM 9-840 it shows the big douglas connector on each circuit breaker is for a two wire connector. All three breakers are connected to each other by one of the two wires in each two wire connector. If I'm reading this right the first breaker has the smaller douglas connector going to the horn and is wire #25. The big douglas connector on this breaker has one wire going to the ignition switch and the other wire going to next breaker as part of that breaker's double wire big douglas connector. The second wire in that double wire connector for the second breaker goes to the double douglas of the third breaker. The small douglas connector on the second breaker is wire #15 and goes to the main light switch feed. The second wire in the double wire connector of the third breaker is wire #10 and goes to the voltage regulator terminal C of the 4 wire regulator harness. And the single wire douglas connector of the third breaker is wire #37 and goes to the auxiliary power outlet on the right hand side of the glovebox on the dash.
So the breakers are daisy chained together by the big douglas connectors you asked about, and each of those big douglas connectors has two wires coming out, not one. So each breaker has 3 wires that connect to it. Now the wiring diagram I'm looking at is from the early M, as it has no provisions for turn signals. And I don't know how many wiring diagrams there are, but I suspect 3. The second would be when they changed the master light switch from having t two connectors (like this wiring diagram shows) to the second itteration where the switch had only one connector. On it. I also think later trucks didn't have the auxillary power outlet on the dash.....so I don't know where the wire from the breaker went on later trucks if they deleted this outlet.
This is getting complicated, isn't it. I think to solve your problem, assuming your truck uses the wiring shown on my diagram, you'll have to make a harness that starts out with a single douglas.........goes to a double douglas.....the second wire in that double goes to another double....the second wire from that double goes to a third double......and the second wire from that last double goes to a single double. The path is single double to the regulator harness....the daisy chain of doubles attached to the breakers....and the last single douglas goes to the ignition switch. I'd scan the wiring diagram but my scanner doesn't want to play nice right now.
So to be sure.....I'd find the correct wiring diagram for your truck serial number.....and make the harness shown for your breakers. Sorry to be so long winded.....I just like typing sometimes.
Oh......if you need to find the double douglas connectors I think both Erik's and Saturn sell them. I think they're like $6 for a half connector....which is all you need since the other half is on the breakers.
Hope that helps (but probably didn't)
regards,
bob
Looking at a wiring diagram for the M in TM 9-840 it shows the big douglas connector on each circuit breaker is for a two wire connector. All three breakers are connected to each other by one of the two wires in each two wire connector. If I'm reading this right the first breaker has the smaller douglas connector going to the horn and is wire #25. The big douglas connector on this breaker has one wire going to the ignition switch and the other wire going to next breaker as part of that breaker's double wire big douglas connector. The second wire in that double wire connector for the second breaker goes to the double douglas of the third breaker. The small douglas connector on the second breaker is wire #15 and goes to the main light switch feed. The second wire in the double wire connector of the third breaker is wire #10 and goes to the voltage regulator terminal C of the 4 wire regulator harness. And the single wire douglas connector of the third breaker is wire #37 and goes to the auxiliary power outlet on the right hand side of the glovebox on the dash.
So the breakers are daisy chained together by the big douglas connectors you asked about, and each of those big douglas connectors has two wires coming out, not one. So each breaker has 3 wires that connect to it. Now the wiring diagram I'm looking at is from the early M, as it has no provisions for turn signals. And I don't know how many wiring diagrams there are, but I suspect 3. The second would be when they changed the master light switch from having t two connectors (like this wiring diagram shows) to the second itteration where the switch had only one connector. On it. I also think later trucks didn't have the auxillary power outlet on the dash.....so I don't know where the wire from the breaker went on later trucks if they deleted this outlet.
This is getting complicated, isn't it. I think to solve your problem, assuming your truck uses the wiring shown on my diagram, you'll have to make a harness that starts out with a single douglas.........goes to a double douglas.....the second wire in that double goes to another double....the second wire from that double goes to a third double......and the second wire from that last double goes to a single double. The path is single double to the regulator harness....the daisy chain of doubles attached to the breakers....and the last single douglas goes to the ignition switch. I'd scan the wiring diagram but my scanner doesn't want to play nice right now.
So to be sure.....I'd find the correct wiring diagram for your truck serial number.....and make the harness shown for your breakers. Sorry to be so long winded.....I just like typing sometimes.
Oh......if you need to find the double douglas connectors I think both Erik's and Saturn sell them. I think they're like $6 for a half connector....which is all you need since the other half is on the breakers.
Hope that helps (but probably didn't)
regards,
bob
Re: Circuit breaker help
Thanks Bob for the long winded 
but good info. My cd doesnt have 9-840. Any chance you could take a photo and email me the pict of the diagram?
Thanks,
but good info. My cd doesnt have 9-840. Any chance you could take a photo and email me the pict of the diagram?Thanks,
Gerry
53 M37
53 M37
Re: Circuit breaker help
Hi Gerry,
I happened to find the harness you're asking about on one of the parts Carter gave me for the red M. The wires are shot, so I can't see any markings on them, but I think the larger (thicker) wires in the double douglas connectors are 12 AWG, not 14 AWG like everything else on the truck. It appears to be all one harness, but I can't find it in the ORD 9. So I'm not sure what the deal is with it.
regards,
bob
DSC04183 by w30bob, on Flickr
DSC04180 by w30bob, on Flickr
I happened to find the harness you're asking about on one of the parts Carter gave me for the red M. The wires are shot, so I can't see any markings on them, but I think the larger (thicker) wires in the double douglas connectors are 12 AWG, not 14 AWG like everything else on the truck. It appears to be all one harness, but I can't find it in the ORD 9. So I'm not sure what the deal is with it.
regards,
bob
DSC04183 by w30bob, on Flickr
DSC04180 by w30bob, on Flickr
Re: Circuit breaker help
Thanks Bob, I think I got it all figured out. Would of been a lot easier if my truck was wired right when I got it
Gerry
53 M37
53 M37