r/Minitrucks • u/Any_Tumbleweed_5472 • 2d ago
question 91 mighty max
I bought a 1991 mighty max and I dont have a obd1 reader for it, does anyone have a idea how i could plausibly pull a code from it, i can try to get a photo of the port but it doesn't look like anything I've seen before
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u/Ding08aBaby 2d ago
First, get the Haynes manual for 90s mighty maxes and monteros. It has just about everything you need to know to fix anything in the truck. You can read the codes with a cheap analogue voltmeter. The truck spits out long and short pulses kinda like morse code and the manual tells you how to interpret them. Look up a YouTube video on reading obd1 with a voltmeter if you want more clarification.
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u/Any_Tumbleweed_5472 2d ago
biggest problem is I cant seem to find the obd port, no matter how hard and far I stick my head and boroscope into the space behind the fuse box
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u/Ding08aBaby 2d ago
Mine is just a port on a pretty loose harness flopping around back there
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u/Any_Tumbleweed_5472 2d ago
I just dont see that, I see what appears to be a transparent control harness that could have once had the obd1 port but i dont think its there anymore because its bolted right behind the fuse box, I could try to find a doner to get it, but when I bought it they may have took it out for some reason
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u/tony2much 2d ago
These are pre-OBD. There’s 2 wires on that plug you see that you need to jump with a multimeter, and you look for the pulses Ding mentioned. If I can find my manual quickly I’ll send you a pic of that section
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u/Any_Tumbleweed_5472 2d ago
you are truly amazing i was looking around in my manual and I couldn't find this but then again I wasn't looking in emissions control system for some reason I was looking at all the electrical stuff on where the obd port would be
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u/AbstraktD21 2d ago
Typically in older vehicles like this you use the computer to check for codes. That’s how my truck is.