99 Buick Park Avenue gas guage broken after work by mechanic

What could cause the gas guage to be broken after the mechanic replaced the rack and pinion and the AC blower motor. (He says it was broken when he received the car. I say it was OK when I dropped it off to him). Also, if the mechanic didn’t cause the issue, what is the best fix? Does the entire dash board control panel have to be replaced, as the mechanic suggests, or is there something else that can be done?

I don’t see how a fuel gauge can become inoperative due to a blower motor replacement or a rack and pinion change.

Does the temp gauge still work? The temp gauge is often tied into the same circuit as the fuel gauge so a blown fuse could be a possibility but this would mean that things other than the fuel gauge are also not working.

The mechanic should not blindly assume the gauge in the dash is the problem. Most fuel guage problems are caused by the sending unit which is located inside the gas tank. The gauge can be checked without too much trouble and one certainly does not go tearing a dash apart without verifying the dashboard gauge is the problem.

I have no answer as to why he thinks the dash must be disassembled first.

I really appreciate the response received from ok4450. The other guages on the dash appear to be working fine, including temp guage. Although, I would not have any way to know for sure the temp guage is accurate. No other guages have gone bonkers, and the other electronic information (gas mileage info, trip meter info) seem ok.

What is involved in diagnosing/fixing the sending unit from the gas tank to the guage?

Just realized I mispelled “gauge” as “guage”. Oh well. No spell checker on this site.

Actually, checking the gauge should not be any more difficult than checking a wiring diagram to see which color wire at the fuel pump connector goes to the tank sender. This wire can simply be grounded against the chassis and with the key in the RUN position the gauge should show a FULL reading.

If it does show FULL then the tank sender is bad. If the gauge needle does not move at all then there is a problem with the gauge in the dashboard or a fault in the wiring between the dashboard and the fuel tank sender.

The tank sending unit should be part of a module that includes the fuel pump. Since the fuel tank is removed to change this module it can get a bit pricy with the labor involved and the cost of a new module.

I’ve tried to think of some possibility that a wiring connector near the blower motor could have possibly been dislodged during the blower motor install but right off the top of my head I don’t see this yet.
I do have some concern if your mechanic is automatically stating the dashboard or instrument cluster must come out when he does not even know what the problem is.

JMHO, but I think in the interest of public relations he should spend 5-10 minutes and check this out (for free) before venturing into wild guesswork as to what the problem could be. There’s nothing wrong with a mechanic or shop showing a little good will here, even if they’re not obligated to do this. Hope this helps.