If you smack the top of the dash the next time it happens, and the gauge comes back, pull the cluster and clean the terminal pins on the back of the cluster. If you have a 98 or 99 TJ (Or XJ) there is a repair connector that gets a better connection to the cluster than the original one.
TSB NUMBER: 08-15-99
GROUP: Electrical
DATE: May 21, 1999
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN NUMBER 08-20-98 REV. A, DATED OCTOBER 2, 1998, WHICH SHOULD BE REMOVED FROM YOUR FILES AND NOTED IN THE BOUND TECHNICAL SERVICE BULLETIN BOOK, PUBLICATION NUMBER 81-699-99003. THIS IS A COMPLETE REVISION TO THE PROCEDURE.
SUBJECT:
Erratic, Intermittent Cluster Operation/Intermittent Air Bag Warning light.
OVERVIEW:
This bulletin involves installing a repair harness containing a revised instrument cluster connector.
MODELS:
1998 - 1999 (TJ) Wrangler
1998 - 1999 (XJ) Cherokee
SYMPTOM/CONDITION:
Some vehicles may exhibit an intermittent illumination of the air bag warning light or an intermittent tachometer or speedometer drop out. An Airbag Electronic Control Module (AECM) fault code - "No Cluster CCD BUS" message will be present.
DIAGNOSIS:
Using the DRB III(R), read and record all active and stored fault codes in the AECM. This condition is caused by minor oxidation of the BUS circuit terminals at the instrument cluster connector. Electrical terminals will show signs of oxidation, which will appear as darkened lines or marks on the cluster male terminals. These often appear as gray or black marks rather than the appearance of oxidation or corrosion usually associated with higher current carrying circuits. This condition will set a "NO CLUSTER CCD BUS" message. The fault code will usually be stored and not active. THIS TECHNICAL SERVICE BULLETIN WILL NOT ADDRESS FUEL OR OIL PRESSURE GAUGE ISSUES. If this fault code is present, either active or stored perform the Repair Procedure.
PARTS REQUIRED:
1 05016261AA Cluster Connector Patch Harness
1 04856975 Electric Contact Cleaner
2 04778570 Heat Shrink Tubing
POLICY: Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
Labor Operation No: 08-90-90-91 0.6 Hrs. "
It says that the gas gauge is not an issue with this, but I've fixed them by cleaning all the terminals on both plugs. 2000 and above already have the new style connector, and many older ones have already been fixed, gut the problem still occurs. Cleaning the connections again will fix it for at least a year or two.
The cluster will come out in about 5 minutes. Take off the lower knee panel, the upper defroster vent (Pull it straight up)to get to the cluster bezel scfrews/ Remove it, then there are four screws that hold the cluster in. The cluster will pull straight out, and the connectors, which are fixed to the dash will come off. With the cluster off, inspect the flat pins on the back of the cluster. You will see little black spots of corrosion on them. Scrape them off with a pick or small flat bladed screwdriver. Clean them with electrical contact cleaner. Apply dielectric grease,and reinstall the cluster
If the sender were going bad, or the circuit to it was intermittantly open, the gauge will read higher than normal, or over full in the case of an open circuit.
If smacking the dash and cleaning the connections to the cluster doesn't work, then there is an unlikely chance of a bad ground to the sender unit, or a short between the ground and the sender unit signal wire.
The only other possibility, is that the gauge in the cluster is bad, but it's also unlikely.
