91.5 Brain Box??????

[GHarman]

Can anyone tell me what that box is under the left fender, left of the battery? Is it a computer? What does it control? Thanks. GregH

 

[KOG]

Yep, that's the engine computer. Controls grid heaters, alternator regulator, A/C clutch, OD on automatics, water in fuel/wait to start lights, speed control, tach, and auto shut down relay.

 

[JGrefenstette]

that little black box sure does control every thing. i replaced it today becuase my truck quit charging the battery. after replacing the alternator and testing the battery, we narrowed it down to the ECM. after i replaced it, the charging system works now, all my dash lights are finally acting as they should, mainly the "wait to start" and "water in fuel", and believe it or not, my SPEEDOMETER is working again!! i dont know if its just a crazy coincidence, or if it truely was linked to the ECM somehow. but im happy! to say the least.

 

[GHarman]

JGrefenstette, If I may ask, How much did the ECM cost? I occasionally have speedometer and dash light issues. So far no battery charging problems. Thanks, GregH

 

[Makaio]

Greg,



I purchased an ECM from an online Dodge dealer about 2 years ago. I don't remember exactly where; someplace on the East Coast. Anyhow, it was about $224 plus shipping to Hawaii. Although it's a rebuilt unit, the purchase was outright.



Aloha,

Matt

 

[JGrefenstette]

GHarman, i got the part for roughly $140 after i got my $125 core charge back.



its been almost a week and everything is still working ok, except the speedometer! it went out agian yesterday. talk about frustrating. just when i thought i had it finnally solved and done! but the dash lights and everything else is still working good. two days ago i had the radion playing, headlights on, wippers goin, and the A/C on, and the voltage gauge was still reading good. that was satisfing.



hope that helps,

jimmy g.

 

[DValentine]

Jimmy, I have had two reluctors go out on my truck. It is a piece that changes the mechanical motion to electrical impulse. It hangs just to the drivers side of the transmission, screwing on to the speedo output. Got new ones at Napa.

Ha Ha on me. I didn't read your post about the PCM first. Sounds like you are on your way.

Dave

 

[JGrefenstette]

dave,

i didnt know i could get parts for that "gear reducer" or whatever its called. ive found the entire unit, but for every vehicle except the old dodge cummins. so you where able to find the "reluctor" from napa? did it solve the speedo and odometer problems???

 

[DValentine]

My speedo was hit and miss, work and then not and then finally nothing. I didn't know what was going on. Took the dash apart and nothing made sense. I finally replaced the box we are talking about. I don't have the part number but it was only 2 years ago that I had the problem. It happened again and I bought another box from carquest. It is not cheap. I don't know if the word reluctor is correct but it is a gear box and changes mechanical to electric pulse, as far as I know. I'll do a little research for you and see what I come up with.

Dave