wiring

TOM R · Post by **TOM R** » Mon Nov 12, 2007 5:48 am

well the ign switch shorted out so I got a new one but do not see where wire 85 hooks to, my old and new switches are 4 wire and i pulled the old 1 before the new arrived, we have 5 manuals and none list that wire #, oh and we are workin on the 54 m37

also are there fuses somewhere, with the new switch i still have no power and everything was ok before the short

pfrederi · Post by **pfrederi** » Mon Nov 12, 2007 6:22 am

#85 is not used in M37 (It is paired to 27) 85 is actually a low airpressure warning hook up.

#11is your hot feed going to terminal A on teh switch

No fuses in M37 only circuit breakers. #11 should come from the breakers under the dash but is the feed for them and is not itself protected by them (at least as I read the wiring diagram. Sounds like you have an open/bad connection

Power starts on #10 (terminal c on the regulator) #10 becomes #11 after the first circuit breaker (horn) then feeds each subsequent breaker before heading to the switch.

TOM R · Post by **TOM R** » Mon Nov 12, 2007 6:43 am

ok thanks

MSeriesRebuild · Post by **MSeriesRebuild** » Mon Nov 12, 2007 9:25 am

pfrederi wrote:#85 is not used in M37 (It is paired to 27) 85 is actually a low airpressure warning hook up.

#11is your hot feed going to terminal A on teh switch

No fuses in M37 only circuit breakers. #11 should come from the breakers under the dash but is the feed for them and is not itself protected by them (at least as I read the wiring diagram. Sounds like you have an open/bad connection

Power starts on #10 (terminal c on the regulator) #10 becomes #11 after the first circuit breaker (horn) then feeds each subsequent breaker before heading to the switch.

#85 was used on M37's, you won't find it listed on a common wiring diagram because it's used as an accessory lead to power up things like the fender mounted heater fan motor. In this case wire #85 is part of the heater wiring harness & will be included in an original complete heater kit. Has all the necessary splices to get hooked into the ignition switch. Like this gentleman said, #85 is used for various functions on other vehicles also. The fact you have wire #85 on yours indicates it was used to power up a heater fan or some other accessory that needs power only when the ignition is turned on.

rixm37 · Post by **rixm37** » Mon Nov 12, 2007 2:54 pm

Are all M series harneses the same? Will a jeep harness fit an M37?

MSeriesRebuild · Post by **MSeriesRebuild** » Mon Nov 12, 2007 3:13 pm

rixm37 wrote:Are all M series harneses the same? Will a jeep harness fit an M37?

No, I'm afraid it isn't that simple.

TOM R · Post by **TOM R** » Thu Nov 22, 2007 7:28 am

ok got a delema here put in the new ign switch and new spider harness on the gauges, the rest of the harness looks new, the truck ran before the ign wiring shorted, i now have no power at terminal 11 to power the switch, there is power coming from wire 10 at the power box, i pulled the glove box and gauges and cannot find any breakers in the dash BUT the following plugs are not hooked to anything

#8
#37
#37/38 double to single
#400
#36
#25

where are the breakers located? or did someone rig this when the replaced the harness?

MSeriesRebuild · Post by **MSeriesRebuild** » Thu Nov 22, 2007 9:40 am

Wire #10 goes from the regulator terminal to the breakers behind the instrument gauge panel. It then becomes wire #11 that jumps from 1 breaker to the other for power up. If you have no breakers installed, it's impossible to tell what about the wiring may have been altered since we can't see & inspect what you have. I'll try to help if you can offer more detail.

TOM R · Post by **TOM R** » Thu Nov 22, 2007 1:19 pm

ok all fixed, i did not realize the breakers were just big plugs, problem was the #10 wire was pulled out of the pin in the cannon plug for the regulator lookied like it was not properly soldered in so dismantled the plug resoldered and reassembled now it starts fast every time

thanks for the help

TOM R · Post by **TOM R** » Thu Nov 22, 2007 5:22 pm

ok now that the ign is fixed I need to test the fuel and oil gauge to find out why they do not work, i replaced the gauge harness so power is not the problem, what is the best way to test em? unhook the sendors and ground them to see if the gauge moves?

MSeriesRebuild · Post by **MSeriesRebuild** » Thu Nov 22, 2007 7:49 pm

TOM R wrote:ok now that the ign is fixed I need to test the fuel and oil gauge to find out why they do not work, i replaced the gauge harness so power is not the problem, what is the best way to test em? unhook the sendors and ground them to see if the gauge moves?

If wire #36 is not hooked up, that goes from the oil pressure gauge to the sending unit. #25 is the horn or should be unless altered.

TOM R · Post by **TOM R** » Fri Nov 23, 2007 6:17 am

well the horn does not work either, guess I am missing some wires?

rixm37 · Post by **rixm37** » Fri Nov 23, 2007 4:25 pm

I guess when I asked if all harnesess for m series are the same I meant are the numbers for where the wires go the same like the 85 number you are talking about?

TOM R · Post by **TOM R** » Fri Nov 23, 2007 5:48 pm

ok 2 more questions, when you flip on the ign switch should all 4 gauges jump? only 2 of mine do and they are the 2 that work

second does the horn plug into the base of the column near the steering box?

Lifer · Post by **Lifer** » Fri Nov 23, 2007 8:01 pm

Your fuel guage should jump and your ammeter should show a slight discharge when you first turn the switch on. The temp and oil pressure guages won't show anything until you start the engine. Once the engine is running, your oil pressure should come up to the normal operating range and your ammeter should return to the center if the batteries are fully charged or show a slight charge if they're not. The temp guage will come up as the engine warms up.