Cadillac Repair: service soon light, cadillac brougham, intermittent fault

Question
I have a 1984 cadillac brougham & the service soon light is on & has been for quite awhile.  My boys used it in college & brought it back last year. I've been driving it and it runs fine. I don't want to take it in to have the light reset.  Can I do it myself or is it something I have to have a mechanic do?  Thanks, Mike

Answer
If you have a problem with the computer system of the vehicle the light will come back ON after we CLEAR (erase it).

If it comes back ON, I need to know what code or codes appear on the display.


1. Turn ignition switch to the ON position. Do NOT start the engine.

2. Simultaneously push and hold the OFF and WARMER buttons on your climate control panel for 3 seconds and release them.

3. If you have any faults in the system CODE numbers will appear either ONCE or THREE times and then go to the next code number and will finally stop at .7.0.

4. Simultaneously push and hold the OFF and HI buttons until you see .0.0 and release them.

5. Turn off ignition switch.

6. Start and let the engine run or drive it for 10 minutes and see if the light comes back ON.

7. If it does NOT, You had an INTERMITTENT fault that fixed itself.

8. If the light DOES come back ON, Repeat steps 1 thru 3 and let me know what CODES you get.

9. Turn ignition OFF.