Oldsmobile Forum - Oldsmobile Enthusiasts Forums

Hello out there, I am a new member to this forum, new to Oldsmobile and new to GM, for that matter.

Anyway, I recently purchased a 1991 Olds 98. It is in really good condition and it came with all of the service records. It has 51000 miles and so far I am really enjoying it. I have found 1 problem though.

When I reach 75mph, I get a rapid ding, ding, ding, ding. It is the same tone you get when you leave your headlights on or leave the keys in the ignition with the door open.

I thought it was probably some kind of feature that could be activated/deactivated to keep you from traveling over 75mph. And it does happen at exactly 75mph. I have clocked it with a GPS. It stops immediately at 74mph and does not sound at any speed below 75.

I contacted my local GMC dealer parts-service department and was told that there was an overspeed module located behind the glove compartment that would sense highspeed vibration and sound a tone if say, a wheel was out of balance. They asked if the car had any kind of high speed shake. But, it does not, it is very smooth at all speeds. They told me that the module had probably failed and needed to be replaced. That was last week. I contacted them again, today, to purchase the part and repair it myself.Of course I got a different tech. He told me that he had been working on these cars for 25 years and I had him stumped. He didn't know anything about this part nor has he ever heard of these cars sending out a tone at a specific rate of speed. Now I am stumped. I have referred to the owners manual and searched the internet but can't find anything. Any help is greatly appreciated. Thanks for your time.