12V system and RFID push button start

[M99821T]

First post! Got the itch to pick up a HMMWV last summer (first military vehicle), and I found 86 M998 2-man for a really good price on Gov Planet. The inspection on Gov planet listed quite a few "issues" (no working exterior lights, dripping leak from transfer case...), but it had the front winch, 100 amp 28/14V alternator, 6.5L, and was refurbed in Maine in 2007. 5,300 mile on the odometer. Do they reset the odometer after refurb? Long story short, received it in late October and was pleasantly surprised that all the lights worked and the leaking transfer case was actually a drip in the undercoating.

I decided to make use of the dual voltage alternator so I could add some security features. I picked up a Bussmann 15303-2-2-4 waterproof relay/fuse box and roughly followed the thread below.

https://www.tacomaworld.com/threads/diy-build-and-install-a-bussmann-rtmr-fuse-relay-block.399454/

Pictures of the battery box with relay/fuse box connected. One of the batteries was dead when I received the HMMWV, so swapped the mil batteries for Optimas. Relay/fuse box and 14V from the alternator are connected to the rear battery (first battery in series; the one connected to ground).





Connections on the side are for 5 fuse circuits and connections coming out the bottom are for the 5 relay circuits. I connected 3 relays to the accessory function on the push button start.



Wiring...cables and wires into and out of the battery box went through an existing hole next to the shunt, along the frame rail tied to the starter/24V supply cables, and up to the engine compartment through a channel in the body behind the dog house.



I ran the cables and wires along the base of the windshield to a fuse holder and then to the alternator.





I know others have done similar things, but I just wanted to share my version.

Jared

 

[porkysplace]

Odometers don't mean much in a military vehicle , if there are any problems with one they just put a different one in .

 

[M99821T]

RFID push button start

Black box is the RFID ignition module. I am using 24V relays with 12V coils to switch RUN and START. I didn't want to modify the vehicle harness, so I made small harnesses that plug inline and/or use mil terminals. Three wires on the left replace the STOP RUN START switch (24V, RUN, START). The red wire on the right plugs inline with the switched side of the brake switch. The 24V from the brake switch is connected to a small 1.5 amp 24V/12V DC-DC converter, and the 12V output goes to the ignition module. Waterproof connector in the middle is 12V from the battery box, ground, and accessory output to switch the relays in the battery box.



Everything is sort of temporary right now, but I mounted everything with adhesive velcro to the bottom of the Smart Start box. Probably will do a engine swap of some type in the future.



Finally, the start button.



First push of the button (without foot on the brake) is accessory mode. Second push activates ignition (glow plugs). After the wait light goes out a third push and hold with foot on the brake engages the starter.

Jared

 

[desmodromic]

That is super slick. Nice work and welcome.

 

[DCIV]

Wow...I’m jealous of your abuilities! I couldn’t do any of that!

 

[M99821T]

Odometers don't mean much in a military vehicle , if there are any problems with one they just put a different one in .

So no telling how many miles are actually on it. Maybe I got lucky and it's the original one.

 

[M99821T]

That is super slick. Nice work and welcome.

Wow...I’m jealous of your abuilities! I couldn’t do any of that!

Thanks guys, it's not too complicated. Just takes some planning and google.

 

[DCIV]

How about you figure a remote start for this thing, it’s been talked about but no one has done it.

 

[M99821T]

I will look into it. Shouldn't be too difficult as you would probably just have to tie into the neutral safety switch so you can't start while in gear. For the push button start, I just looked at manuals online to see which manufacturers had the features appropriate for the HMMWV. I used DigitalGuardDawg PBS-II. If you had more time and programming skills than me, you could do it with an Arduino or Raspberry Pi and a couple relays (<$100).

 

[98G]

So no telling how many miles are actually on it. Maybe I got lucky and it's the original one.

Maine RSMS set it to zero at rebuild. It's probably accurate for your engine but not the chassis.

RSMS basically set it to as-new anyway. Sounds like a good truck.

 

[M99821T]

Maine RSMS set it to zero at rebuild. It's probably accurate for your engine but not the chassis.

RSMS basically set it to as-new anyway. Sounds like a good truck.

Good to know. Thanks!

 

[TechnoWeenie]

Video of RFID start pls?

 

[M99821T]

Video of RFID start pls?

Here you go. The fob is set to manual mode (push unlock button to activate instead of automatic with proximity) so you can see it activate. Cold start and 40 degrees in the garage.

https://youtu.be/__1bpB_mRVY

 

[TechnoWeenie]

Very nice.

 

[TLangM998]

Awesome set up! What would you say the total cost was?

 

[M99821T]

Probably around $800 but I bought a lot of extra waterproof terminal parts, wire and specific crimpers. I won't have to buy anything when I install accessories in the future. You can find the RFID system for less than $500. You can get RFID kits for ~$40, but you get what you pay for...

 

[Mammalian04]

M99821T, with all the crip tools and connectors at hand, would you be willing to fab up another plug and play harness for the Digital Guard Dog? I reached out about 24v system while they were at CES but they didn’t respond. I will try them one more time (since they MIGHT have a 24v system for construction equipment) but if I get no response, I’d like to go the route you did.

 

[NormB]

Nice work, Jared. I enjoyed seeing this.

Keep those posts and photos coming.

Norm

 

[M99821T]

M99821T, with all the crip tools and connectors at hand, would you be willing to fab up another plug and play harness for the Digital Guard Dog? I reached out about 24v system while they were at CES but they didn’t respond. I will try them one more time (since they MIGHT have a 24v system for construction equipment) but if I get no response, I’d like to go the route you did.

It would be a very straight forward modification to make it compatible with 24V. I guess it just depends on if there is a big enough market to justify it for them.

Here is the 24V-12V DC converter I used for brake switch.
https://www.amazon.com/gp/product/B01EFUHG5C/ref=oh_aui_detailpage_o01_s00?ie=UTF8&th=1

12V coil/24V switched relay
https://www.mouser.com/ProductDetail/655-V23234-B0001X001

relay harnesses like this (remove center wire)
https://www.amazon.com/10-Pack-Inte...517292358&sr=1-31&keywords=relay+harness&th=1
packard connectors
http://www.eriksmilitarysurplus.com/rushcoq20msa.html

I'll post a wiring diagram when I have some more free time.

 

[Mammalian04]

Hey gentleman, I got hold of Bruce at Digital Guard Dog. He is going to put together a plug and play unit for us. I'll update here when progress is made.