I have a Case 1840. The backup alarm starts as soon as the key is turned on. Does anyone have any suggestions?
The backalarm has power to it at all times with the key on through the pink wire. The black wire is the ground to the alarm and is open until both reverse pressure switches are close. Check the black wire and you will find it grounded out somewhere, probably were the harness goes over the bellhousing is the most common area.
Thanks Goose, The new backup alarm (not from case, but from an autoparts store) has a grounding plate on it, so it is always grounded. Do you think that could be causing my problem?
Most certainly, yes. That's why that grounding plate on the new back up alarm is removable, some applications, such as this one, do not require it. Welcome to HEF robthebuilder. :drinkup
Thanks for the reply & thanks for the welcome willie59. I was a member several years ago, but with the children, building a new house, & working all the time I have not been on. I guess all my information was erased after being inactive for so long. I am glad the forum is still here. Thanks for the help. I plan to be on more than once every 6 years now!
Just an update, I removed the grounding plate, it did not help. I cannot get the alarm to work at all now. I cleaned all the ground wires on the transmission, the battery ground, and tried a different backup alarm. I decided to rent a bobcat for a few days while I try to fix this one. It is cheaper (& safer) to rent one than have to pay a fine for not having the alarm working. Does anyone know where I could find a new wiring harness for this machine?
rob, Before you go replacing wiring harnesses - have you checked the switches? There are 2, one for left & one for right. If one of them is stuck in the closed position the alarm will sound.
Drat...alrman beat me to posting the diagram. Power is at back up alarm as soon as you turn on ignition, controlling the alarm is a matter of controlling ground to alarm. This is done by two pressure switches wired in series at the drive pumps (items 2 in diagram). Don't go and replace your harness just yet (keep your wallet in your pocket). Even if it turns out to be a problem with harness, if the only thing that's having a problem is back up alarm, we can run a single wire to repair failure in harness. Another possibility, as noted by alrman, is one of the two pressure switches is bad, that's all it takes to kill back up alarm, lets start with testing them. You're going to have to open things up and gain access to pressure switches at drive pumps. If I recall the 1840 correctly, you can remove the seat and not have to slide cab forward, which requires disconnecting harness to cab, we don't want to do that. Removing seat pan won't give you a whole lot of access, but maybe just enough to do what we need. If removing seat pan gets us enough access, turn on ignition, then connect a ground wire to each of the 4 terminals of the two pressure switches that control back up alarm. When you find the terminal that activates alarm, you've found the master ground input to the two pressure switches. Move your ground wire to the opposite terminal of that switch. Start machine and drive in reverse with both levers. If alarm activates, that pressure switch is good. If it doesn't, that pressure switch is bad, put a jumper across the two terminals so we can test the other switch. Move your ground wire to one of the terminals of the other switch, drive in reverse. If alarm activates, we could be simply grounding the ground input to that switch, move ground wire to opposite terminal of that switch, drive in reverse. If alarm activates, that switch is good. If not, it's a bad switch. If you don't get any alarm from grounding one of the four terminals, problem with harness. Simply run a single wire from back up alarm to the pressure switches to repair bad ground circuit.
Thanks for the help alrman & willie59. I did not have time to work on it today, but I will definitely use the above information & suggestions this weekend. Until I get this thing fixed I will have to deal with the Bobcat 185 I have rented. Powerful machine, I just hate the foot controls. Thanks again
Keep us updated rob.