Seat belt replacement (but now radio doesn't work)

[schardein]

2 hours ago, Virginia said:

No. Here's a better picture.

 

That looks like the buzzer, arrow in red.  It's the black box, so it has a buzzer for the seatbelt not fastened and for the key in ignition with the door open.  It won't have a headlight on warning, the blue box adds that feature.

 

The seatbelt warning should come on when you start the truck, and then stop after about 10 seconds whether you fasten the seatbelt or not.  Did it ever work?  I am trying to figure out if your issues could be related.  I'm not sure, just brain storming.

[AZJeff]

I dug around in my 1990 shop manual, and I found the wiring diagrams related to the seat belt chime system, plus the radio and clock systems.

 

A cursory scan of those diagrams makes me think you have killed the ground to a bunch of stuff by cutting that wire to the seat belts, but I have not spent a ton of time tracing all the paths.

 

I have attached the diagrams in some PDF's for you to dig into further.

CLOCK WIRING.pdf RADIO.pdf SEAT BELT.pdf

[Virginia]

5 hours ago, schardein said:

That looks like the buzzer, arrow in red.  It's the black box, so it has a buzzer for the seatbelt not fastened and for the key in ignition with the door open.  It won't have a headlight on warning, the blue box adds that feature.

The seatbelt warning has never worked.

 

5 hours ago, schardein said:

The seatbelt warning should come on when you start the truck, and then stop after about 10 seconds whether you fasten the seatbelt or not.  Did it ever work?  I am trying to figure out if your issues could be related.  I'm not sure, just brain storming.

 

[Greenjeans]

Were you happy with the quality of the seatbelts?  Retract hood and all that?  I need some (2 door XJ) and I’m looking at the options.

[Virginia]

Yes. Seemed well made. If what I have fits your model, you can have them for shipping costs. This is what I bought

 

https://www.ebay.com/itm/374308355755

 

 

[Pete M]

On 7/3/2023 at 7:42 PM, Virginia said:

The set I got don't fit. I'll give you the part number when I get the right one.

 

 

did I miss this in the thread?  I think I might suggest new belts to the owner of the truck I'm working on.

[Virginia]

You didn't miss it. I just posted it. The ones I ordered don't fit my mj but might fit the xj

[Greenjeans]

Sorry I misunderstood.  I thought you had purchased a set from the seatbelt website that was posted.  

[Virginia]

Sorry. On hindsight, I should have 

[Virginia]

I took the female side of the seatbelt apart today and found this. I took these just to show the series of what I found when I took them apart. The third one is the important one, I think. The black wires were connected to those copper spade looking things. My guess is that when the male side of the seatbelt was inserted, it either made or broke a circuit. I can tell because when I opened it, that little white piece at the tip of the spade connectors sprung so I don't know if it was pulled back under the tips or was like it is now, tripped forward. The black wires are labeled "A" and "B" but I can't find a diagram that I can read that shows me what color wire the "A" and "B" were connected to.

 

The pdf files I was sent are too small for me to read. I'm checking my chilton to see if it shows.

 

Am I even close to correct with me theory?

[AZJeff]

Virginia,   I posted the wiring diagrams for the 1990 model year, and I seriously doubt if those circuits had a color change in the wires for 1991 (the year of your MJ.)

 

I would check those if I were you.

[Virginia]

Yes, I know you did AZJeff but when I download and open them the print is tiny and if I try to enlarge, the writing gets blurred. Either way, I can't read it.

 

I went back and tried to read them again. It was a little better but I can't see anything that goes to a green and black wire and a solid black wire that is spliced in at the back of the cab.

 

[AZJeff]

4 hours ago, Virginia said:

Yes, I know you did AZJeff but when I download and open them the print is tiny and if I try to enlarge, the writing gets blurred. Either way, I can't read it.

 

I went back and tried to read them again. It was a little better but I can't see anything that goes to a green and black wire and a solid black wire that is spliced in at the back of the cab.

 

That's odd.  I downloaded one of the PDF's I uploaded and was able to open it  using "Preview" on my Mac computer.  It's not crystal clear, but I can read all the text when I blow it up to a size bigger than 8.5 x 11 inches.    I will try it using Adobe, and see if it opens clearly or not.  If necessary, I will figure out another way to capture those pages in a bigger format.

[AZJeff]

The wires to the seat belt switch, in the 1991 manual I have are shown to be a black one and a white one.  These, of course, are not the colors of your two wires  

 

Others have mentioned that they suspect a ground issue, and I think they are on the right track with the root cause of your problem.

 

The circuit is very basic for that seat belt switch.  One end goes to power on the chime module, and the switch just completes the ground to the other side.  I outlined this is blue on the attached diagram. The location where it completes the ground is a common ground for a ton of stuff, so my inkling would be to ground one of the wires and see what happens.   I know that kinda sounds kind of a guessing approach, but since the wire colors don't line up, it's worth a shot.

 

[Virginia]

I'm gonna try it. I can connect the black to the black wire marked "B" and the green/black to the "A" wire then ground and see what happens.