2016 Terex R070T intermittent door(?) switch.

[Brushwolf]

Bought a used 2016 Terex R070T with about 800 hrs on it but with a replaced engine a couple years. Apparently it was run out of oil and was a leased machine used by a landscaping company before I got it. This has a cab and front glass door that will not open unless boom arms are fully lowered.

Worked fine for about a month and then it for no apparent reason stopped all hydraulic functions (boom, track), though it would start and all the accessories worked. Being I was brushmowing in the woods at the time the boom was not all the way down and I was trapped in it. Had to crawl out the back window.

Found the overhead console loose and the door safety switch is mounted in that. Fiddled with it and tightened the bolt holding the console and it worked for a while again. Have checked wiring for all 3 switches (door, safety bar, seat). Any of these malfunction then all hydraulic functionality ceases.

Since then I have had it work for a month or two, then not work, then work after let sit a week or two. Crawled out the back window again last winter while pushing snow. Let it sit a month and used my old 1958 Case loader for awhile and eventually went back to the Terex and it worked again.

Have taken the overhead console down, set the door switch plunger further outward in the console so door gasket pushes it in further. Worked intermittently again. Can be driving along and all hydraulics just stop suddenly, like someone slammed on the brakes. Crawled out the back window again last week.

How can I be certain the door switch is defective and where can I order a new door switch online if that is the problem. I will not remove or bypass the 3 switches, but if I did the last one I would ever remove would be the door switch. Just begging for injury or expensive front door damage doing that.

Terex is a very handy little machine and still less than 1000 hrs on it. But in a pinch I will just go use the old 1958 Case instead cuz that always works. But I do not have a tiller or brush mower for the Case..

Any suggestions besides hauling it 100 miles to a dealer with locked tracks...?

 

[foton]

my suggestion is to use a digital vom on ohms on each switch activate and release each switch several times and make sure each time the switch goes I would say less than 1 ohm. If you get no failure it could be a harness issue.

 

[Brushwolf]

Regular multimeter? Or a different device? Electrical testing is not my strong suit..

Thanks for the reply BTW. I also posted about this issue January 2021 and never got one response on that post. Figured cuz it was either an unusual problem or not many forum participants are familiar with this machine.

 

[foton]

yes a multi meter but I think to make it easier to read ohm readings this low would be to use one that does not use a scale and a needle but a display that will be much easier for you to read.

 

[Brushwolf]

Do I need to disconnect the battery when testing switches? Or just disconnect each switch before testing it?

And a working switch will show the negligible/zero ohms when in the off position and a high ohm reading when it is in the ON position?

I am not sure how these switchs are supposed to work, but I have read that they have magnetic components which I do not fully understand. Are the magnets supposed to move components inside the switch to activate and deactivate them?

 

[Brushwolf]

I do have a digital multimeter but have not used it much..

 

[foton]

if you can unplug each switch and test them would be best, I do not know on your machine how it works whether they are normaly open or normaly closed, off hand I would guess normaly open so when you lets say sit down the circuit closes and the voltage goes to the next safety switch.

 

[Brushwolf]

Well the door switch, the lap bar switch and the seat switch all work. That probably leaves only the "occupancy presence" safety solenoid itself that these 3 switches work together to activate.

I have a new solenoid and valve but cannot figure out where they are located on the machine itself. I have only been able to find diagrams that show the parts, and where they connect via hoses to other components,, but not where they are located. The service manual available online only shows parts and nothing about how to locate and replace them.

Do not see them in engine compartment, do not see them inside cab or under floor or behind seat even after removing most of the interior. When the rain let's up I suppose I will have to remove the shielding panels underneath it and see if they are under it somewhere..

Anyone know where these safety system solenoids are physically located on a Terex R070T? Or where to get a more detailed service manual that may have better info?

 

[Brushwolf]

Found the solenoid and valve. Replaced with new but still nothing changed. The block holding the solenoid and valve are under the front of the fuel tank, so only require seat removal and bolt at top rear center of fuel tank. Block up the front of tank and you can access the block and its solenoids and valves. Unfortunately for me it changed nothing though I put new solenoid and valve in. Did not appear anything was wrong with the removed components either. O rings on valve looked fine, no noticeable contamination anywhere.

Now wondering if there is a relay that powers the valve that is failing. Probably should have checked that earlier, but like I said electronics is not my strong suite...

 

[Master_Tech]

You can purchase from dealer or online (eBay) a bypass cap that screws onto the door sensor to keep it pressed in, this is designed in case you want to remove the door

This is a simple way to bypass door sensor if that is your issue

Another option is to buy a 10 omhs resistor and bypass the wiring to the door switch if this works then you know that the switch is faulty.

Note. The bypass cap sometimes does push the switch far enough in so using a piece of rubber or something hard to put inside the cap before screwing it on

 

[Jim A]

I just got that same Machine at auction.
Chech your pump to engine mount bracket and bolts.
Mine were cracked loose busted which snapped hydraulic pump flanges off pump .
I rewelded and added more steel and reinforcement to hold pump on motor which vibrates bad at certain rpm.
That Perkins 403d-13 is used by CAT also . A good engine.
Good