I am the proud owner of a 2000 MC SS with the 3800 Series II.

A bit of history on the car first.

My oldest son bought the car and I bought it from him. It was then 'given' to my next oldest son to drive. While he had it he took it upon himself to install an aftermarket radio, amp and subs. That has all since been removed when he bought his own vehicle. When I reclaimed the car to get it ready for my daughter to drive when she gets her license I went to start it on a cold morning and the upper intake blew up. This was caused by a leaky fuel pressure regulator valve. This has now been replaced and the car is running good again.

Now for my little problems.

First is some dash lights. My brake light and my air bag lights are on. I checked the wires under the dash and everything looks fine. No frayed or broken wires as was suggested elsewhere in the forums. Just wondering if these two lights have anything in common or where the wires may be running together?

Second problem is my heater controls. When I switch to floor, dash, defroster, etc. the air isn't redirected. Are these still controlled by vacuum or is this electrical in the MC?

Third problem is my temp gauge. Sometimes it reads and sometimes it doesn't or is inaccurate. When the gauge doesn't move my low coolant light is on. If the gauge works I get no light. I have checked the coolant level and it is full. I have replaced the thermostat and temp sending unit and bled the system. Any ideas of what to check next?

I'll stop at those three. the rest are little annoyances that I can get to later.

Thanks in advance for any help.

 

ok I am not sure about the cel lights. but with the interior vents I am pretty sure the actuators went bad and stopped working. It sounds like they need to be replaced because it is not diverting the heat to the floor or any where. It is controlled by actuators and the heater/ac box is also has them as well. With the temp sensor I would guess I would follow the electrical lines or have a multi meter hook it up and run acontinuity test on it to see if there is a break also a test light as well

 

Thanks. Hopefully tonight I'll have time to check a few things out. I hate electrical on cars but I'll break out the multimeter and do some checks.

 

OK, tried checking the wires and couldn't find any broken, frayed or otherwise damaged wires.

In addition to the problems above I have also found some other problems.

Neither engine fan works. I have connected both directly to the battery and the motors are fine. Checked the fuses and wiring and those are fine too.

The battery will drain if the car sits for a couple days.

Now this one is weird. Whenever I change the station on the radio the 'tone' control goes back to manual.

After reading some other threads I am leaning towards the problem being the BCM. Are there any checks I can do to either confirm it's bad or rule it out as the problem?

 

As far as your tone issue when chnageing stations is normal....
Once you set the channels with the tone setting you want/like..
It should stay that way! you mesan like when it says,classical,country, rock,news etc.... Correct?

 

Yeah, where it says rock, classical, etc. What happens is that I can set it to rock, tune to another station and it will change to manual. When I go back to the station that was set to rock, it will stay on manual. I have to manually change it again. It's not keeping that setting.

 

OK. Some of the fixes I have found.

First is the fans. They will not come on until the engine reaches a certain temp. My thermostat was stuck open so the engine never reached the right temp. I replaced the thermostat and all is well. The engine neats up much faster and the fans will turn on when needed.

I still haven't figured out the radio tone thing yet but that's at the bottom of the list for right now.

The air not deflecting like it should, vent, floor, def, I found a broken tee connector on a vacuum line. It is at the back side of the upper plenum. I repaired this and the air now deflects as it should. So, YES, the actuators are vacuum controlled.

As for the dash brake light. I feel like an idiot but the fluid was low. Topped it off and the light is out.

Last thing is the air bag light. Still haven't had a real chance to dig into this one yet so if anyone has any ideas about this please let me know.

 

Word of caution.... It's been my experience, if brake fluid is low, there is a reason. Typically it's a leak in the brake system (other possibility is last time the system needed bled it was not properly topped off). Keep an eye on it to see if you loose fluid.

As for the air bag, if you can access a good scan tool, it can tell you what the air bag codes are. If the car ever had the steering column pulled out, my first guess would be a broken clock spring (it's the device that maintains the connection from the column to the air bag in the steering wheel and allows that connection to maintain when the wheel is turned). If not, it could be any list of things.

Best of luck!

 

If you have side airbags in the seats then check under both front seats around the yellow connections. I fixed my light this way when I spliced the wires back together under my drivers seat