Does anyone know how to wire the backup alarm on a first series D3? The wiring on mine is gone. The diagrams I can find in the parts manual/service manual make no sense. thanks.
Are you missing just the wire or alarm also
Power from the oil pressure switch through the transmission mounted switch then to the alarm and ground.
I have the alarm, but the wires are cut from the alarm going forward.
The only switch I can find on the transmission is the safety switch that prevents it from starting when in gear. The book shows it going from oil pressure to a switch somewhere on the trans, but I don't see how the alarm circuit could differentiate between whether the trans was in forward or reverse. Also, the circuit is only completed when in neutral.
Serial number would be helpful.
ser. no. 79u0811
Need to add switch, bracket, etc.
What operates the switch?
I show the machine as a 1974 model. Many machines of that era didn't have back up alarms installed from the factory. They were an option that the dealers installed. Lots of machines got a pressure switch that plugged into oil pressure to the reverse clutch pack. You should see a switch on the transmission control block valve on the transmission itself if it has that. I've also seen plenty of machines with the mechanical micro switches that get pushed by some part of the mechanical linkages that go from the lever down to the transmission control valve.
There are no other switches I can find. Not sure what the transmission control block valve is, or where it is. Thanks
I just removed mine the other day. Could do some more looking if need be, but the power came thru the harness on left side. Then power goes up to horn button up by shifter and also goes to backup horn
If you take some panels off you can follow the rods and connections all the way down to the spools on the transmission control valve.
What kind of switch for the backup alarm, where is it located, and how is it activated? thanks. is that where the shift linkage connects to the transmission?
I'll have to go look, will try tomorrow Yes, take the panels off around the throttle and shifter
Back then I use to put on mechanical switches. Would mount switch so when put shifter in reverse it would hit spring and and engage back up alarm.
Did you epoxy the spring on? That looks like a good idea as the linkage is a little sloppy, and finding a switch that would fit exactly would be very hard. Did you mock up the one in the photo, or are they available like that to purchase?
Found all the wire and connectors tapped up but no switch. Connectors are on left side and looked all over but unable to find anything that resembles a switch on the trans
No ,that’s how It’s made . You have to figure out to mount it Bolts ,U bolts zip ties whatever you want. Look up mechanical backup alarm switches . Also used hose clamps.
The oil pressure switches are just a knob screwed into the transmission control valve with two spades sticking out of the top. There may be threaded holes in the spades or they may just be blanks. Look for wires that hook onto the spades.
SIS shows mine having the switch mounted on the trans cover and actuated by the shift linkage. That said I don't have a shift linkage, have cables
Found the D3 parts book online in pdf. Look on page 49 (27A) and part number is 6S6861 Found same info on SIS using your SN http://www.tractorparts.com/PDFs/CAT_D3_TRACTOR_79U1_TO_79U4708_PARTS.pdf https://parts.ringpower.com/inventory/Part_Details/530B/NA/6S6861/UCA
One thing I have forgotten to ask was if either machine was a high stat trans. The other item is that some machines had the engine throttle control on the transmission control handle. Places for switches will be different.