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Hello ol' grouch,
Thanks for the information you have shared with me. It's helped a lot. It never occurred to me that there would be a brain box on any application before 1980. Anyway, I did a search for an 85 Dodge D150 brain box and I keep coming up with a bunch of different things, including ignition modules, which someone says is a brain box. I'm sure your not talking about an ignition module. However, I haven't a clue as to what one looks like, even by your description. I'm a hands on learner. Illustrations are great too.
Is this a brain box?
Well, yes and no. It's the brain box for the lean burn ignition. What you want is this one;
Until they went to fuel injection, the basic ignition was that one. There are other components that looked similar. It has the 5 prong plug. They are cheap and reliable. I have had them fail. They can be pesky to track down. I had one that worked fine when cool but hot it would fail. I've seen a simple thing like rust keeping the body from grounding too.
It is named an ignition control module. Brain box is slang and I'm an olde pharte. I think the young snots at most parts store wouldn't know what a brain box is either
If you distributor was replaced(as you said the motor was) the lean burn module won't work with it. They had two pick up coils in them. It has a history of problems so why would you put one in.
It is named an ignition control module. Brain box is slang and I'm an olde pharte. I think the young snots at most parts store wouldn't know what a brain box is either
This is one of the first parts I replaced as it was melting down the firewall. I guess I'm one of those snots that didn't know the term "brain box," though I'm not young. LOL. I'm pretty sure if I went in to O'reilly as said I need a brain box. They'd probably say, "What in the heck is that?" Except there is one ol' timer that may know what it is. He been there ever since they put it in about 10 years ago.
So, yeah, I replaced everything, including the ignition switch. I also cleaned the wiring connectors for the wiring harness that sits just above the passenger side of the engine and put new dielectric grease in it. So, I am at a road block with why my truck won't fire up. I did see your post about replacing the wiring harness. I'll check into it, but I think I'll just by pass the pink wire, as I think it's the culprit. Thanks for your help.
Thea
I shall not give up. It will not beat me! It ran before, it will run again.
the pink wire is the one from the ballast resister to the positive side of the coil. it also goes from the ballast resister to the starter relay. it should be very easy to test. could even just use jumper cables from the battery to the coil for testing purposes. the truck should either start or not if that is truly your issue.
Last edited by crazzywolfie; 01-24-2023 at 03:04 AM.
\Start and run witch should be battery volts. If you are not getting that in run or crank you have a problem Also inspect the ballast resistor and the terminals/wires going to it, They tend to heat up.
Thanks for the diagrams. This is the one I have. I have replaced everything, from the ignition switch to the ignition solenoid and everything in between. The only other thing it could be is the wiring from the ballast and the ignition control to the distributor. OMG, this is a nightmare! However, it ran before, it will run again.
if you think you may have more wiring issues it may just be worth the $25 and buying a new ignition harness. you have likely spent way more than that just getting to this point.
Thanks for the diagrams. This is the one I have. I have replaced everything, from the ignition switch to the ignition solenoid and everything in between. The only other thing it could be is the wiring from the ballast and the ignition control to the distributor. OMG, this is a nightmare! However, it ran before, it will run again.
Ummm.......you have replaced the fuse haven't you? When I had a shop, I got the occasional car or truck in with a minor, but hidden problem. The box melting down the fire wall suggests high current going into it.
Do a voltage check on both the red and blue wires, Of course it will be lower on crank because the starter robs a good amount of power. What are you getting?
The box melting down the fire wall suggests high current going into it.
no it doesn't. i would also suggest never leaving one of them ignition modules in a glove box or toolbox without putting it in a bag. i would also suggest painting the back to try and limit how much goo comes out of the back of them. maybe the new ones are sealed with something better but i have had similar things happen with a spare ignition module i had in my glove box. it didn't leak too much of the sealant out but was extremely hard to remove from anything it got on.
Ummm.......you have replaced the fuse haven't you?
Where would this fuse be? Is it a fusible link? I did find a fusible link tucked into all that wiring along the firewall, but I haven't a clue what it goes to. Or if you're talking about the fuses under the dash, they are all good. I've decided that I am going to install a new distributor, as the shaft is slightly bent on the one on my truck, however, the truck still ran with it bent. The new distributor I am going to put in is an HEI. The ignition coil and the ignition control module are built into the cap. I believe this will eliminate my problem. However, I don't know if this fuse you are talking about will interfere with this new distributor, so I need to know where the fuse is so I can check it out.
It ran before, what ever it takes, it will run again.
01-22-2023, 12:42 PM
