I have a CAT 226B serial number: MJH08353. I need help locating the door bypass harness, my machine has an open cab. I've been having an issue with the parking brake and seat belt light flashing and the machine wont move. I've read that this bypass can cause issues but I'm struggling to find where it's located and how I can go about testing it.
It's on the LH side of the cab up behind the headliner. I'll send you a (searchable pdf) electrical schematic. Look for CONN 35.
Thank you Nige. I'm going to head out to the machine in the next hour or so to see what I can find. Other than a visual inspection of the connection to the bypass, is there a way to test it with a multimeter?
The schematic has details of the bypass harness in Grid I-8 on Page 14. All you have to do is jumper Pin 2 and Pin 4 on the machine side (marked CN-C22 on the schematic) of CONN 35.
I just realized I needed to order the Deutsch pins and crimper in order to make the jumper wire so I ordered those. I do have a question after opening up the cover to access the bypass. These three connections (see pictures) don't have anything plugged into them. Do they need to be capped or have a bypass attached? I also included a picture of the front of the cover.
Those three connectors are for optional features. The two large black ones are certainly for switches. I'm guessing that you probably have a number of blank plugs in your LH overhead panel. You can identify each switch function by looking at wire numbers/colours on the connector then relate then to the schematic. I don't know of any blanks for the larger connectors but you could put a 2-pin Deutsch socket on the small one if you were of a mind to do so.
Okay thank you. I did order a 2-pin Deutsch socket so I will cap that one for peace of mind.
If nothing has gone t1ts-up electrically behind that panel in the 17 years since the machine was built I can hardly see that changing now. My 2c, YMMV.
Lol I'm sure your right but I bought it used and I don't know if anything has been tampered with.
Isn’t that white jumper wire in the 6 pin plug above your hand the door bypass already installed
After looking up the wires (T901-CN67 YL -18 and T902-CN68 PK -18) for the 2-pin, if I'm looking at the schematic correctly, on page 14 grid F-9, it shows the wires connecting to this "mss exciter coil". I'm not sure what the exciter coil is, I think it has something to do with the machine security system but I'm not 100%. Is this something that should be there for my serial number that you know of? I do have the Machine Security System indicator on my RH panel but the indicator is not on.
The coil is for the activation of the Machine Security System. IIRC it detects the proximity of the “smart ignition key” used by MSS-equipped machines. I would say that at some point someone has removed it.