What are these for

[JeeperjohnfromPA]

OK on a 1987 4.0, with an automatic,

what are these two connectors, under the hood on the passengers side, that have little yellow covers? Are these for some sort of diagnostic unit? or something else. I've labeled them A and B and am holding the caps in my palm.

Thanks in advance for the info.

[mjeff87]

diagnostic test ports.

 

Hang on a minute and I'll post up a pinout so you can see all the points....

 

Jeff

[rockhardzj]

You know OBDII on newer cars?

 

Well, that's Jeep/Renix OBD B.C.150 :D

 

OK, drop the BC150 part... It's the on board diagnostics ports

[DirtyComanche]

The real question is if you can actually tell anything with it?

 

 

Never used mine for anything. If it was being a pile you could tell why by looking at other things.

[rockhardzj]

My sister's wrangler showed a bad O2 sensor before...

[86FUBAR]

The diagnostic ports work prity good and tell u a fair amount of info , i was surpriesed at just how much info they give . i tried to hook up our snapon scaner to mine the other day and it did nothing (worked last time i used it :hmm: ) owell she still runs

[87manche]

The real question is if you can actually tell anything with it?

 

 

Never used mine for anything. If it was being a pile you could tell why by looking at other things.

 

you sure can.

things like fuel pump voltage, and a myriad of sensors can be accessed right there.

technically you need a DRBII

but I've had good luck with a multimeter.

[skimore11]

I wired my VHF radio into one of those to pick up power. There is a switched power and a constant power in there. I just pulled the yellow cap figured out which pin I needed and then covered the connector with electrical tape and poked through the one hole I needed. The wire I was using was tined so it was stiff. Worst part is thats my best wiring under the hood. :eek:

[BarracudaBlueXJ]

yea i have a carbed 4 banger with those and was always "like yeah those are gonna do me a lot of good"