Yellow Box removal / Seat belt interlock delete.

Hey guys. Thought I would post this in the event someone else like me finds a dirty big wire from their starter solenoid to the wire loom from the yellow box. Also people who have removed their bench seat from their 74 and installed buckets or people who simply wish to remove the yellow box and red over ride button from the engine bay.

I read the instructions found on this fine forum and followed them however I found the two wires that needed to be cut and joined together were actually four!

There are five wires to the button. Two red with green stripe go to one point, two white to one point and there is one single red wire. Cut the red / green stripe wires and the two white wires. Join the red ones together and the white ones also. Then join all four into one and tape up to the loom to keep it from getting wet etc. You can cut the single red wire and tape it up also. The button can then be removed entirely.

To remove the yellow box un screw the mounting and unplug the loom from the rear. Tape it up somewhere safe also.

If you have a wire bypassing the system because you no longer have the seats or it was malfunctioning simply cut it. If you had cut this wire prior to the button mod you would have found the car would not kick over.

I am not an auto sparky so take my tips with a grain of salt. I did follow most of the tips found here but given my own wife doesn't listen to me, be your own judge. Cheers.

 

Amazing that yours was still connected after all these years ... I imagine most were butchered withing the first year of ownership.
If you set a bag of groceries on the passenger seat, it was possible that the car wouldn't start .... grrrrrrr ......

 

Yeah. I thought id cut the wire from the starter solenoid first just to see if it worked and sure enough when I tried starting it nothing. Deleted the switch and she started again no problems.

 

My 74 still had the whole set up. Im doing mostly custom wiring by customizing the original harness. so hopefully it wont mess with me too badly

 

I have to delete mine as well. I always wondered what that button and yellow box was for.

 

I did this years ago, and was AMAZED at how many wires went in and out of that box. Seems like it was 20 wires, just to bypass a seatbelt. Seems like they could have done it all with three wires...

 

In reading up on it there is a lot of features to prevent people from trying to cheat. In addition to the weight sensors in the seats there are also switches in the retractor mechanisms and latch buttons. All this is to make sure when someone is sitting in the seat they actually pull out the belt then click it - all in the proper order or it won't start. Way too complicated for 1970's technology!

 

I'm just curious, what exactly is inside that yellow box? Is it just a bunch of mechanical relays or was it advanced for its age with some type of primitive circuitboard?

 

I dunno what's inside the yellow box, never dealt with one.

As far as circuit board, by '74, were becoming quite advanced(though microprocessors were yet to make appearance). In consumer products, had been around for over 20 years...

 

Good point. I remember ‘74 was the first time I used a calculator, I think they had been around awhile but my 9th grade civics teacher brought one in and let us calculate our grades. And weren’t electronic ignitions beginning to be offered around then?

 

You're correct, I bought my first calculator in early '70s. Had itsy-bitsy LED display and ate batteries like they were candy. Outside of similar devices, microprocessors were still in the future of auto industry.

I believe '74 CA vehicles were first to get electronic ign, followed by all '75. Those units were analog and continued till Ford introduced the TFI ign module. Still I believe modules are mostly analog, but are controlled by EEC-IV computer.. First used on '83 Turbo Coupes.

 

David