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74 charger identify this part?

Hijinx

Hijinx

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What is this relay for? whats it called and/or where can i pick up a new one?

20190216_124446.jpg
20190216_124501.jpg
 
Seat belt interlock relay. The rubber button on the bracket side is the reset button.
 
that is the seatbelt interlock relay, I've never tried to buy one , I just bypassed that problem causing stupid little thing. check ebay
we must have been posting at the same time
 
I disconnected the relay, and unplugged the harness under the seat, and the seatbelt light didn't come on.
 
the real name is the interlock reset button, not a relay really. Is just to bypass the cranking interlock seatbelt system in case of failure or making some mech fixes on engine bay, being able to crank up the engine from the key without fasten the seatbelt.

once pressed will allow to crank it up for some time jumping yellow wires inside. It gets a bimetallic piece inside that when gets cooled down, it "engages" back the interlock system cutting out the internal jumping made when you press down the rubber button.

You can bypass it just jumping out both yellow wires on the outside, straight at the plug and still can keep sensors hooked up allowing to make work all the warning system controled by the interlock box.

Interlock seatbelt system works also with passenger seat.

They float on NOS on ebay quite often
 
NOS 74 reset button
https://www.ebay.com/itm/NOS-MOPAR-...=item58bc9b5071:g:GrwAAMXQlrxRcq~I:rk:10:pf:0

Reset button is really hard to beat mainly because I think is barelly used ( if you had to use it a lot is because you never fixed whatever was wrong on the interlock system ) , but they use to get ugly due the harsh enviroment they live. Mostly sure your unit is still in perfect working conditions.

And these are the control boxes for 74, blue for auto, tan for manual, orange for Canadian models which were not interlocked to the cranking system, but is just a warning signals brain box. All boxes handle key in buzzer, fasten seatbelts light and buzzer and lights on Buzzer ( if equipped with the correct buzzer because was optioned ). Located on a bracket between glovebox and ashtray down the dash frame.

https://www.ebay.com/itm/NOS-Mopar-...c:g:GE8AAOxycmBSvNE0:rk:2:pf:1&frcectupt=true

https://www.ebay.com/itm/NOS-Mopar-...h=item48a8553098:g:GjMAAOSw5RRaefm9:rk:7:pf:0

https://www.ebay.com/itm/Mopar-NOS-...2:g:1KoAAOSwe9tcXa5C:rk:4:pf:1&frcectupt=true


on 74, diff than earlier models where each function got its own buzzer, it got an only one buzzer for everything, being this plastic piece used just for seatbelts on 72/73

https://www.ebay.com/itm/Mopar-NOS-...h=item442e945fbb:g:VUQAAOSwX~dWo6Vy:rk:3:pf:1

when lights on buzzer option was equipped, this was the unit equipped ( harness plug allows both buzzers, is just about change it if you want to add the lights on buzzer feature on your car )

https://www.ebay.com/itm/NOS-MoPar-...h=item4d5a23811c:g:5hQAAOSwLF1YATgb:rk:7:pf:0

This ( these ) buzzer are attached on the passenger side of dash frame, close to glove box light )

And Horn relay for 74 is 3 prongs one mounted on same location than earliers, but earliers got a 4th prong to handle the key in buzzer on same unit

https://www.ebay.com/itm/1974-75-76...=item2ce4d841f6:g:~-0AAOSwj0NUlL4o:rk:32:pf:0

This is the horn relay for 71/73s with the integrated key in buzzer ( can be used on 74s, just the 4th prong won't get conected with any wire )

https://www.ebay.com/itm/NOS-OEM-Mo...h=item1a58dcd70c:g:WwEAAOSwcmBbUmAP:rk:9:pf:0
 
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I can't say I'm an encyclopedia because all this is a continuous learning process. Since I'm overseas I have to reduce as much as posible the mistakes buying stuff because I wouldn't be able to return it but buy again. So trying to save anything as posible I get in deep as posible searching the info.

On this case, Venezuelan Mopars didn't got 3 points seatbelts nor the warning systems on those years ( my car seatbelt light was wired like 71s, time delay flasher controled ). I don't feel comfortably driving a car without a 3 points seatbelt so wanted to get the correct 74 seatbelt setup for my car, warning system inlcuded. It took me maybe 3 or 4 years but got all its parts.
 
i was debating buying the interlock reset button, but if i need to sit down and buckle in for the car to start, i rather bypass it. Sometimes you just want to start the car from outside without getting in. My only concern is if i bypass it by connecting the 2 yellow wires that nothing else might go wrong such as a seat belt warning light staying on or the car not starting. But bypassing is the way to go i think.
 
just jump it out at both yellow wires on reset button plug and done. No need for hack up the wiring. Not even need to disconect anything else of the warning system. You will be able to get it back on any moment. Just a jumper wire between both cavities even still with reset button switch in place.

I bet reset button is still in working order, just looking ugly outside.

Another option, is get an orange control box ( there are couple on ebay on $20-30 rate at this moment ), and change the box you could get at this moment, and won't even need to jump anything, because the orange box is already jumped inside.

I have an orange box at this moment on my car with everything connected
 
well no i pushed the button in and it's stuck... doesn't snap back, clicked when i pushed it in but subsequent "pushes" no more clicks. There is a NOS one on ebay for 125. But yeah, going to clean up the old one and jump it.
 
This is a pic that I took looong time ago of the orange box on my car. Despite the green circles on left side because were made for another reason, but pay attention to the bigger one on right side. Note BOTH yellow wires are jumped into the PCB. This is a non interlocked unit orange ( Canadian ) box

P1070016a.JPG
 
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Hijinx said:
well no i pushed the button in and it's stuck... doesn't snap back, clicked when i pushed it in but subsequent "pushes" no more clicks.
Click to expand...

It just clicks once to engage the internal jumper! after engine is started up, RUN circuit and ground will reset it heating the element inside and will snap it back the button. If you want, feed blue and black wires to dissengage it. That will make the full test to check is in working order.

at this moment, yellow wires must get continuity. Once blue and black wires heats the element inside, yellow wires continuity will be cut.
 
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This is a PCB from a damaged blue box I have in hands. Just took the pic ( the other pic is maybe 10 years old LOL, took with an old Nokia 6275 ). Try to note the same tracks on PCB ARE NOT jumped! Hard to notice but is visible.

Allong with some other electric components being diff because there is no need for those because the orange box won’t block the cranking circuit, These jumped ( or unjumped ) tracks on PCB makes the difference to feed the cranking circuit without pay attention to the seatbelt status

4F5604A7-261E-417D-BA51-F9E530755A4C.jpeg


Have to insist My car is ready for the blue box ( I got in fact a NOS blue box long time ago that I haven't installed yet ) but is working CHARMING with the orange box installed without anything jumped, just changed the box. All warning systems working as must be, including the lights on warning buzzer which I added just changing the buzzer from the yellow 2 terminals one to the gray 4 terminals unit I shown.
 
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The simplest thing I have read to bypass the seat belt interlock system was to unplug the seat pressure sensor switches under all the seats. No splicing or re-wiring needed.
 
But will miss the warning signal system.

Nobody has said splicing or rewiring, just a jumper wire at reset button between both yellow wires, that's all. No need to disconect anything. Can be done with reset button still plugged and install the jumper from back of the plug.

Another job can be made is swap around the yellow wires at engine harness plug to bulkhead!
 
Thinking out loud and something I never have done is if you try to crank the engine throught the window it should crank, because if ppl claims disconecting the seat sensors the interlock system is "bypassed" that it means like if nobody seats, engine will crank! Something to try! Maybe we are overthinking this
 
Nacho-RT74 said:
And this is the tech masters conference video I found couple of years after I understood how the system works LOL ( and well, I have the 74 Parts Manual catalog )

http://www.imperialclub.com/Repair/Lit/Films/314/314.mp4
Click to expand...

Wow, cool video! I book marked it. I wonder if there are any of those testers floating around?

My first car was a 1974 Dodge Charger hardtop and I remember having to deal with this system. It was my daily driver even through winter lol.

Scanned copy of the Polaroid picture from 1979 lol.
IMG_20190219_0001.jpg
 
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