Chevy C60 OBD Connector?

Pig · Jan 28, 2021

I have a 1988 366ci Chevrolet C60 that we've been using on the farm. Great dump truck, that's still in decent condition.
Recently the CHECK ENGINE LIGHT has come on, and I am not sure where or how to get the code to display. I presume this will work by blinking CEL, if only I knew how to get it to display.
I certainly can't find an OBD1 connector. There is a three prong socket at the fuse box (that looks a little like a household 110V socket).

Does anyone know how to read the CHECK ENGINE CODE for a 1988 Chevy C60??

Pig · Jan 29, 2021

Old Doug · Jan 29, 2021

There should be a connecter under the dash you cross the 2 far right upper row together while the switch is in the run position.Is it not running right?

Coaldust · Jan 29, 2021

It should have a ALDL connector somewhere.

Pig · Jan 30, 2021

Thanks for the replies!
Let me go take another look. I couldn't find any connector before....

Old Doug said:
Is it not running right?

It's running fine, with no noticeable issues.

Pig · Jan 30, 2021

Looked again, and can't find a OBD/ALDL connector.

I mean, the truck works okay, but the Check Engine Light being on IS kind of annoying!

John C. · Jan 30, 2021

I don't remember any OBD connections in 1988. The one make that sticks in my mind was Ford with their EEC V systems and no OBD until the mid nineties.

Pig · Jan 30, 2021

Well, there's a Check Engine Light, that would indicate that it's sensing SOMETHING wrong. I'd just like to find out what it is!

djhutt · Jan 30, 2021

I had an 87 c60 and an 86 g30 that if I remember correctly had an orange 8 or 10 pin inline connector under the hood on the driverside fender that I jumped the end 2 terminals and it would flash codes with the check engine light

4x4ford · Jan 30, 2021

That plug is for a turn signal flasher

Pig · Feb 8, 2021

Well, I looked under the hood, and there's no OBD/ALDL connector there either.
Maybe it's time to look at this from a different angle: as I can't seem to find out what the error code is that is throwing the Check Engine light, maybe I should investigate ALL possible reasons for it. I mean, there can't be THAT many things that will trigger the CEL, surely!

Does anyone know what to look for? What are ALL the possible reasons for a CHECK ENGINE LIGHT on a 1988, 5.7l, Chevrolet C60???

Axle · Feb 8, 2021

That 3-prong plug on the fuseblock is for a 2 pin flasher on c10/20/30's. Thats about all I can accurately say about it.
What kind of fuel control is on an 1988 c60? carb? tbi? fuel injection?
HEI still used in those? (has a vacuum can) Or a distributor with a single plug in connector on the base?
Not that I'll be much help, but if anything is similar to the light duties, might be able to come up with some ideas.

Pig · Feb 8, 2021

Thanks for 3-prong socket clarification!

it has a Holley 2-barrel 2300 (4412) carb.

Old Doug · Feb 8, 2021

Have you tryed to clear the code by removing the bat cable? Maybe it was a one time deal.

Pig · Feb 18, 2021

Old Doug said:
Have you tryed to clear the code by removing the bat cable? Maybe it was a one time deal.

That was a good suggestion, and I was hopeful this would 'fix' it, but alas....the light is still on.

4x4ford · Feb 18, 2021

I’m really thinking that with a carb that there really isn’t much of anything to set a check engine maybe check the temp sensor and oil pressure sending unit to make sure there isn’t a broken wire not really anything to be computer controlled on that

Delmer · Feb 18, 2021

I can't help much either, all I know's OBDII was required in 96, but that might be different for heavy duty also. Best guess is to compare it to the similarly equipped pickup and look up how to read the codes on those. Maybe find the ECM and find the pickups that used that also?

Vacuum leaks were a big thing back in those days. I never knew GM though, so I don't know how much they relied on vacuum.

Mike Van · Feb 18, 2021

If that link comes through o.k. it's just to a bunch of youtube videos about Chevy chttps://www.google.com/search?sxsrf=ALeKk03rvqwzrVDesL1fQt-Mmx20gX-edg%3A1613684992691&source=hp&ei=AOEuYPmgJ-nl5NoP1puykAU&iflsig=AINFCbYAAAAAYC7vEGYzQUrQXp23JzXOqMPP9_5Z8dsI&q=1988+c60+check+engine+light+codes&oq=1988+c60+check+engine+light&gs_lcp=Cgdnd3Mtd2l6EAEYAjIFCCEQoAEyBQghEKABMgUIIRCgATIFCCEQqwI6BwgjEOoCECc6BwguEOoCECc6DQguEMcBEK8BEOoCECc6DQguEMcBEKMCEOoCECc6BAgjECc6CAgAELEDEIMBOgsILhCxAxDHARCjAjoCCAA6CAguELEDEIMBOgUILhCxAzoFCAAQsQM6CAguELEDEJMCOgIILjoNCAAQsQMQgwEQRhD7AToGCAAQFhAeOgkIABDJAxAWEB46BQgAEIYDOggIABAIEA0QHjoLCAAQyQMQCBANEB46CAghEBYQHRAeOgcIIRAKEKABUKfOAViVrgJgnsYCaAFwAHgAgAGzAYgB8RGSAQQyNS4ymAEAoAEBqgEHZ3dzLXdperABCg&sclient=gws-wizodes - Hope it helps -

mks · Feb 19, 2021

On the pint sized versions I believe they would be above your knee when sitting, pointed down.

Axle · Mar 7, 2021

If its got a carb the only thing it might have is some version of Electronic Spark Control, if your distributor has a vacuum can, it won't even have that, and was probably converted to a standalone HEI.
On light duties, pre-obd, w/esc the module was bolted above the glove box, it might have given up the ghost and is what is triggering the light.

If you elect to remove this box (assuming it is esc, and assuming it has a stand-alone distributor) you might lose powert to the distributor, if so, just got to back track the switched power feed for the esc (large red wire) and find the inline connector underhood. (usually in the distributor area in the firewall harness, might be loomed up)
Disconnect, and connect the switched feed directly to the distributor BAT terminal. Assuming no previous hackery, the in-line connector plugs right into the distributor. Presto, no more esc, and if you unplug the esc, no more related dash lights. I'll emphasise again this is based on older light duty trucks, but it may give you some extra ideas of what it is you might be looking at.

Chevy C60 OBD Connector?

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