Ghhofstetter

Hi,

First time poster, but been reading for a while... Finally got an account when I had something to ask. I reviewed many threads regarding this topic, but none helped me fully.

I have a 1999 sport 4.0... I was working on some audio problems when I blew a fuse. I realized that my instrument cluster, dome light, key fob, and radio stopped working. I read some things up on this forum, and got everything to work (except the instrument cluster) by replacing a blue 15 fuse under the hood.

My instrument cluster lights up, but no fuses are broken. It reads no bUS, from what I read, means there is a problem connecting to the car computer. I have pulled the instrument cluster, and checked the grounding wires. Everything looks great...

Is there something I am missing? Is there a lone fuse I forgot to check? I'm pretty defeated right now cause I can figure this out...

thanks to anyone who can help

Grady

Radi

Did you check ALL the fuses, including those in the PDC under the hood?

Ghhofstetter

I did..., quite a few times, but according to the panel, none of them actually connect to the dash...

If there is a single fuse you can point me in the direction of (besides the instrument panel dimmer). I'll replace it just to test things out.

Thanks

CCKen

Did the instrument cluster work before you did the audio work?

Check fuse #9 in the Junction Block (passenger footwell). The Instrument Cluster is powered through two fuses; the IOD fuse in the PDC (which you've changed), and fuse #9 in the JB.

Ghhofstetter

Sure did, I even replaced it for full measure...

If it isn't the fuses... Then i must be missing something...

The grounding wires for the dash are near where it plugs into the computer (front right when facing the engine) right?

Thanks again

Ghhofstetter

I forgot to answer this question, yes it did

CCKen

No, the instrument cluster is grounded under the dash, on the far left side. This ground circuit rarely gets broken/open so I wouldn't be concerned about it for now.

If you're interested in grounds, there are two ground points in the engine bay that have caused the No bus problem due to corrosion. One ground point is called G101 and the other is called G100. Pics below show the locations. Diassembly of these grounds and cleaning the wire terminal ends with Scotch-Brite pads and tightly reassembling them has cured a few No bus problems. How this would relate to your audio problems, I don't know, but give it a try.

However... there is one more ground in the engine bay that is related to audio, it's the braided strap that goes from the firewall to the #14 bolt on the cylinder head. This 'ground' strap is used for radio noise suppression but is also an alternate ground path from the engine to the chassis. You may want to diassemble this ground point as well and clean the ring terminals/replace or wirewheel the bolt Pic below.

A note on G100: The bolt that secures G100 may be corroded in place and if bad enough you will snap the bolt head off trying to get it out, or you will break the weld nut loose in the fender. Use penetrating oil on this bad boy before attempting to remove.

Try these things and see if it helps.

If you don't own one, get a quality digital Volt/Ohmmeter (not an autoranging one!) because you may need it for further troubleshooting.

G100:



G101:



Radio Noise Supressor:

Ghhofstetter

Alright, no change....

I pulled them off, cleaned them and reattached them... even threw in another ground cause the G100 was so far gone...

Thought I had it, well shucks... so it isn't any fuses, isnt the grounds...

So, if i understand right, that means either the instrument cluster itself is bad (which I dont think it is... was reading perfectly before the audio fuse blowout) or the connections behind the cluster (all seem pretty clean and untouched...)

If I were to redo all the connections behind the cluster, how do you pull them out further from the window... they seem pretty tight up in there

or if you think im going down the wrong path let me know

Thanks again on this tough problem

JeepBountyHunter

I've got a similar problem with my 93, and hadn't realized this was posted as I started my own post. I did the ground points too, and have no tach, and poor readings for the fuel guage....

CCKen

You'll need to check the CCD Bus, so you'll need a quality Digital Volt/Ohmmeter.

I've posted in several threads on how to do this if you'll take the time to search around.

If you can't find anything I'll get back to you on what to look for.

Ghhofstetter

https://www.cherokeeforum.com/f2/dlc...r-obd2-162775/


You mean this thread? I'll follow and get back to you

XJlimitedx99

this occasionally happens in my jeep. every time its happened ive just kicked the wires under the dash and the gauges come back

CCKen

This is not the one. Try Googling "No Bus, Cherokeeforum.com", or "No Bus/Instrument Cluster Not Working".