I am having some really weird electrical issues now. Right now all three bulbs behind the HVAC controls are out as well as all of the lights where the headlight switch and fog lamp buttons are. Also the fog lamps are not coming on. I have checked all of the fuses and all of them are good. I did notice a fuse labeled "SCM" that requires a 10A. I was just curious what that one does.

I have a feeling that all of these just burning out all at the same time is too much of a coincidence. I think that there is something else going on here, but it has exceeded my electrical knowledge capacity.

Any ideas would be really helpful. I am trying to avoid taking it to the shop just to spend a couple of hundred dollars to have them tell me something maybe one of you guys can.

Thanks!

 

I believe that is a SIREN CONTROL MODULE. you might need to have it scanned by Volvo to see what codes are in it.

 

I have the electrical diagrams for a 2005 Volvo S40 T5 AWD. The Fog lights and the instrument and control illumination are somewhat related. Both go through the ECM and use fuses 4 and 18 (check those). The fog lights use relay 4 and the switch that controls the fog lights use relay 1. check those. I am not good at these systems, but I will e-mail diagrams to someone if they want to take a look and try to help.

Let me know.

 

I have checked all the fuses I can find. There is one fuse box under the hood and then one down by the hood latch on the inside.

Do you think I could have a faulty ECM? How many other problems would a failed ECM produce?

I know those things are expensive, so I am hoping it's something else.

Thanks for the help

 

Check relay number 4. See if it pulls in when you turn on fog lights. Use a friend to stand with their finger on the relay. Do the same for relay 1 when you turn the key to pos II I believe. I am talking from memory right now. I doubt its the ECM. Probably a short. If you have a multimeter check the battery pos to car frame and tell me the voltage.

 

Check voltage with key in pos II

 

I will have to figure out where the multimeter is cuz I just moved, but I actually have an update. First I cannot tell you which fuse is which because they are not numbered. Also there are 7 relays but only three are numbered. I would assume that they are numbered left to right from top to bottom, but that is just a guess. So will that relay test work even though the foglights do not work? It seems that if the button for the fog light doesn't do anything then the relay wouldn't work, but does that confirm the relay is bad.

One other issue that I am having now is that there is a 10A fuse in the main fuse box under the hood for "marker lights". This fuse consistently blows out. I have replaced it about five times. That tells me there is a short somewhere, but I have no idea how to track it down.

 

HEY, i am pretty sure this is NOT the right vehicle, he has a 2004 1.9t, completely different vehicle, sorry charlie.



FlyBoyd
I have replaced it about five times.


After the first time you should of known there was a short. What is this fuse number and location again and i will try to help you.

I highly doubt your ECM is bad, but maybe your CEM.

 

SVT,

It's obviously not the same vehicle, but I have never seen a 2005 fuse box and wasn't sure if it was similar. At this point I am looking for anything to work, as to save me from taking it to the shop and pay for them to tell me that I need to replace a cheap part. I would rather try to find the solution myself.

As for the fuse, it is the 10A fuse for the "parking lams" which controls both the side marker lights and the tail lights. I didn't think it was a short at first because the fuse would work and eventually go out, but since my bulbs went out behind the HVAC controls and the fog lights not working, as soon as I put a fuse in there it blows.

So there is a short somewhere and I have no clue where to begin. The only thing that I recently changed was to put some LED wedge lights in the interior, but those work just fine. I also checked the 20A fuse for the fog lights and that is good too. Can you tell me what the CEM is?

Also there is a relay for "engine system". Do you know what that is for?

Is there a way to get a diagram for my car that explains where these fuse lead to and what they are for?

Electrical is unfortunately the one thing I am not really good at. So ANY help would be nice.

Thanks!

 

SVTfocus03, I know its not the same vehicle. No one else is helping so I am doing my best.

Relay for engine systems, maybe charging/starting system??

The CEM is your "Central Electronics Module" and in my car is located below the glove box. This little guy pretty much controls everything auxiliary in your car. Since a lot of your other stuff is working I don't think this is the problem, but I guess you never know.

If you have a fuse thats blowing that helps to locate your short. Shorts suck because you are probably going to have to dig around to find where its shorting at. Did this problem happen right after you added the new LEDs? You could have damaged another wire when you were doing that. Like pinched it when you pushed the light fixture back into place. Also, do you have any water coming into the car anywhere? If you get water laying in a harness you can develop a short.

 

Call me Jason,

anyways, just to clarify some confusion, a 2005 is a completely different vehicle than the one he has, 2004.5 and up is a FORD, and the one he owns, 2004 and down is a Mitsubishi, the differences will confuse you immensely fault tracing.

But give me the number and location, underhood, interior, etc. of this parking lamp fuse, i should be able to find it, but let me know. I believe it is the fuse box underhood, near the headlight fuses.


I will try my best to get back to you Monday 5-17, as I am trying to assist others on here as well.

 

ok,

so you checked all the fuses under the hood?

Looks like fuse 8 controls a lot of things, including CCM, alarm, and some interior lights.

Fuse 23 does the parking lights as well as Fuse 24.

Looks like the CEM controls the instrument lights, parking lights, most all lights. This looks to be a CEM problem, that is expensive.