Erratic Instrument Panel on GM Cars

This is my 1999 Oldsmobile Alero. In early September 2010 the instrument cluster (speedometer, tachometer, temperature gauge, fuel gauge, and various warning lights) stopped lighting up and registering data immediately when I start the engine. When that happened the radio and turn signals worked; but the power windows, door locks, and cruise control were inoperative.

The instrument cluster might work problem free for a few days, but then would not turn on until I had driven a block or two after starting the engine. It did always came on, eventually. Sometimes the instrument cluster failed to work properly each time I started the car over several days. 

Over the years, connections and other things in circuits change to add more resistance to the circuit. This can have a large effect on circuits involving low voltage signal pulses. This Instructable is about removing one source of increased resistance, at least on this model of car. First, here is some general information on instructment cluster problems for slightly newer GM models:

General Motors cars had instrument cluster problems from 2003 through 2006. When I researched instrument cluster problems on the Internet what I found raised concerns in me. Many of those vehicles had problems that began with the instrument cluster, but eventually led to the engine refusing to start. Sometimes drivers were stranded on the road for at least 10 minutes. Those cases usually involved a security warning light showing itself on the dashboard. A friend's speedometer quit working on his Chevrolet Impala and the dealership quoted him a price of $800 to fix it. The car was no longer new, but still had some life in it. He did not want to spend that amount of money and traded the car for a new one.

The problem in those instrument clusters is a stepper motor design that fails. A number of services around the USA can be found on the Internet that will rebuild a GM instrument cluster with new stepper motors guaranteed never to fail during the remaining life of the car. Also, in 2006 GM began issuing phased recalls to fix the problems on vehicles no older than seven years and with fewer than 70,000 miles on the odometer. This business will rebuild your instrument cluster. This vendor will sell the new and improved stepper motors so that anyone with very modest soldering skills and a low wattage soldering iron could easily install the new motors on his vehicle's instrument cluster. You can also buy the new stepper motors at Amazon for about $6 each. If you have one of these GM vehicles and are having problems with your instrument cluster, here is a very good video on replacing the stepper motors.

Although my car works well in regard to everything else, it was not immediately clear to me whether my car used the same stepper motors as those models under the recall. A problem that might result in the engine refusing to start would mean I might have to sacrifice recent upgrade repairs I made (struts, tires, alternator) and shop for a new car. Certainly, I am not about to spend $800 on a car worth only about twice that much on a trade for a new car.   

Step 1 Eliminate other possible causes

A worn ignition switch could be the reason for erratic behavior at the instrument panel. But, removing the ignition switch to check it usually means removing the entire dashboard, and that is a very involved task to be avoided, if at all possible.

This is the left instrument panel cluster (IPC on schematics you might find in a manual for your car) junction block. It can be used to determine if the ignition switch is good or not. A 10 Amp. fuse (red) marked in the key as "IPC/ BFC ACC should be without power on both sides when the ignition is "off," but should be live on both sides when the ignition switch is "on" in any position. There is a ground connection with a black wire at the upper right corner of this junction block. Attach one lead of a multi-meter to the ground screw. Set the meter to a DC voltage setting greater than 12 volts. Use the probe on the other lead to touch the small metallic spots on the top surface of the fuse. If only one of these registers 12 volts on the meter when the key has been turned, the fuse is probably blown. If both sides register 12 volts with readings one after the other, it means the ignition switch should still be good.

Update: Although the tests I used indicated the ignition switch did send voltage through the proper fuse at the proper times. But, the problems I was having came again. I was able to remove the ignition switch and check it for continuity in a series of tests proscribed by the Haynes manual for my car. My ignition switch failed a couple of those more detailed tests. I have now replaced the ignition switch. I published another Instructable on replacing the ignition switch on this model without removing the dashboard.  

Comments

[rimar2000]

Another great Phil B's instructable! Fully detailed, fully explained, good photos.

What a shame not to have a 1999 Oldsmobile Alero, to apply it! ;)

[Phil B]

Thank you, Osvaldo. Automotive engineers tend to copy standard design features from one another. I have no doubt other makers also use metal on metal spring loaded electrical contacts that oxidize over the years. They probably assume we will not keep our cars long enough to have a problem.

[rimar2000]

My 2011 Classic Chevrolet (a cheap car in Argentina) is not bad, I am happy to have it, but some parts are shameless coarse. In example the bumpers, they are too thin, a little touch breaks or deforms them. I think the future cheap cars will be in paper mache!

[Phil B]

You are probably correct. I can remember people complaining how cheaply made new cars are forty or more years ago. Once I complained to a man about how poorly my car was made. I had just met him. Then he told me that before he retired, the factory he managed had made the parts for my car about which I was complaining. I have learned since to be more diplomatic, especially in the presence of people I do not know.