Daily driver w/recent clean bill of health. Sat for 8 days. Opened the door & heard a buzzing noise from front passenger area. Start was OK. Shift to reverse (manual) & all interior lights/gauges shut down. Drove to work, all systems go & no problem. End of day, it would not recognize the FOB. All prestart functions/lights flickered random. Hum is in the Interior breaker panel. From the lower left corner. No hot spots. Humming will stop if I disconnect the large green wire bundle. The humming also stops if I pull the 40amp breaker ("interior panel feed") from the engine area panel. Started car with same symptoms, & drove home. Got a light show the whole way. Flickering warning lights. Tach & speedo were dead. Headlights/windows/turn signals/wipers/& CCU worked- but nothing in the cockpit. The interior breaker panel had a faint smell like the old red paper cap guns. ANY IDEAS on where to start???? My plan is battery first.

 

Update- I need a good wiring diagram for a Volvo C30!!!!! Who has one?? Specifically a diagram of the interior circuit breaker panel.

 

I tested the battery and it is good. I dropped the Circuit breaker panel. The culprit appears to be pin 12 on connecter "front-1". This is the big green connector. There is a green corrosion ring at the base of this pin, that appears to be connecting to the adjacent pins. The pin position in the green connector is lightly melted. I can see some white corrosion on the circuit board through the pinholes in the breaker box. I am about to take the housing apart to check the damage. I would like to know what pin 12 operates- so I can I.D. any damage downstream.

 

The cap gun smell is coming from this connector plug too. Very faint, but only from the housing for "Front-1"

 

As I disassemble the breaker housing- I found the 15 amp breaker for the 12V socket in the rear seat was blown (Position 45). All other fuses were okay. Doubt it is associated, but who knows?

 

The Circuit Board (should be a picture attached)

 

The inside of the breaker box

 

The pin connector. The suspect pin is the 4th one in from the right along the bottom row. slight discoloration is barely visible.

 

I cleaned up the corrosion, and made sure no inadvertent connections were present. I reinstalled it in the car. The car started fine. The FOB works again. No more buzzing, smell, or popped breakers.
The instrument cluster does not work. None of the dials or displays are on. Curiously, I could not find a breaker for anything in the cluster.
Is there an internal breaker, or reset protocol for the instruments???????

 

I am back to square one. The car started and shut down 3 times. Now the arcing noise (hum) is back, from the circuit breaker panel. I have disconnected power, and looking at new circuit boards. They seem to run around 527$.

 

If anyone has the electric diagram for a C30- Please reply. I want to chase down grounding points and possible causes.

I am also curious about the power source for the Speedo/Tach/Cluster screens.

 

Did you look at volvowiringdiagrams.com? They have some years but not all.

 

Many Thanks to firebirdparts. The website is very useful. I was able to download the full tech manual. Highly recommend. www.volvowiringdiagrams.com It did not hit on my myriad of google searches.

 

I have to replace the Central Electronics module Circuit board. This is not a plug and play part- because the memory of my car is stored in the burned board. I found these 2 resources, which are very helpful. Xemodex Inc Technology Improved | Specializes in the manufacturing and re-manufacturing of electronic components for European automobiles is a company in Ontario Canada. They specialize in cloning Volvo circuit boards. I got a CEM from a salvage yard. I send xemodex the burned board (mine) and the salvage board. They will wipe the salvage one clean, and transfer the memory from the burned one. When I get it back, I can plug the Salvage CEM into my car- and it should work as if the old one never left. This saves me hundreds of dollars by avoiding the dealership. I would like to note Eerie Volvo in N.Y. 315-736-8215. They are very helpful. They are a Volvo Only Salvage yard.

 

A new CEM, on line, is running around 527$. I would then have to go to a dealership to get the memory programmed, at whatever labor rate that requires. The salvage CEM cost me 150, and the xemodex transfer is 250. I will post how it goes once the transfer is complete.

 

Update. The salvage CEM arrived yesterday. It was in great condition. I have shipped it off to xemodex, and will post the results when I get the cloned board back.

 

Installed the cloned CEM today, and everything works great. All systems are working again. The instrument cluster is back to life. The mileage is correct, and the car recognizes my keys. I would recommend XeModex. Car is fixed for probably 1/3 of what I would pay at dealer.