I'm having an ignition problem and I just want to make sure my next move is the right one. The problem started as I was driving down the road and the engine (302) misfired a couple times then just cut out. I tested a few things and found I could hotwire the car from the battery to the coil so I'm fairly sure my coil and distributor are okay. That left the starter solenoid and the ignition switch. I changed out the solenoid today but it still wont start without the hotwire. At this point I'm thinking switch but there is one other component in the system that could be involved...I just can't figure out what the heck it is. Underneath the dash is a yellow box containing what looks like a relay and a solid state transistor. The original owner told me that occasionally you'd have to tap the box if the car acted like the battery was dead. Obviously this box has some control over the ignition system but what is it? The closest thing I can figure is that it might be a voltage amplifier for a breakerless distributor...however I have points. The body is a '74 Grabber but the engine is from a later '70s LTD. It is possible that the original distributor was breakerless before the LTD engine was dropped in. I've attached some photos of the box. The part number on the box is D4AB 14A554 (Motorcraft)...the number on the circuit card is 2L7-0311-01. I've seen some previous posts mention a seat belt interlock circuit but I find this kinda weird.
I have always wondered what that box was. I would love to take it out, since it takes up space where the (extra large, ultra loud, multi-amp) stereo should be.
My '74 Grabber has the exact same thing. I disconnected it once a while back to see what would happen, but I can't remember what happend when I did now. I'm pretty sure the car wouldn't start without it connected. My dad said none of his '71 Comet's had them.
Hummm..........my 74 Comet has one of those under the dash too. I figured it was something like a noise resistor for a stereo. No engine in mine so I have no idea.........electronic stuff drives me crazy, especially when it doesn't work........
I've seen the box in the 74 Comet 4dr I use to have. Don't kmow what it's for. But, did know if you unplug it, it won't run...
I would check for 12 volts on both sides of the regulator. You are still running points. Condensers can do stupid things sometimes, have always heard either a condenser is good or bad and no in between. Proved this false on a 29 Studebaker a few years ago to a hard headed owner. Dan
My car originally had points distributor, I swapped it for the Duraspark ignition. I just went out and unplugged it, when you turn the key all the lights on the dash come on like normal, but engine won't turn over, the solenoid dosen't even click. I then connected it back and started the car and disconnected it with the car running and it died instantly and the ALT light and TEMP light poped back on as if I just had the key turned to the ON position without starting the car. I would definately like to get to the bottom of this. I would love to get rid of mine, always in the way when I'm doing something under the dash.
That yellow box is the seat belt interlock system. Car won't start unless seat belts are on. Both front seats have a sensor built into them that "feels" if a person is sitting in the seat and if they have their seat belt on. No seat belt on..........no start. When introduced in 1974..........Ford Dealers got lot of complaints from little old ladies and the like who hauled their groceries home in the front seat. Seems this system thinks groceries is a person not wearing a seat belt.....hence...car wouldn't start. This may be why it is a one year only thing. The system can be defeated by simply unpluging the wires under the front seats.
Here's why I thought amplifier (according to my old Chilton's book): "A breakerless system using a solid-state amplifier module inline between coil and distributor is installed in all 1974 Mavericks/Comets sold in California and some 302 V8 models outside of CA." There is no picture but the drawing shows something similar to "the box". I found this under the Engine Electrical section of the Engine and Engine Rebuilding chapter. However, if it is some sort of interlock then it can be jumpered or shorted I'd think. Regardless, should I change my ignition switch?
Hmm... My car just had wires running into the seat belt buckles which had a switch built into them to turn the feature on or off when the seat belt was buckled. Nothing to "feel". Thats what I did was just disconnect it. How would one go about wireing around the box so that you could remove it, Craig? Thats alot of 31 year old circuitry to screw up at a really bad time...
Mavmike O'Reilly replacement of distributor, but otherwise stock. I have always wondered what that yellow box was.
Weird. Wouldn't it be dangerous if the car was already running? You're headed down the road and your passenger unbuckles...car stops in the middle of traffic!! I agree, we need to figure out how to remove the box from the system since I bet trying to find a new/used one would be pretty hard!
