I'm trying to track what appears to be an electrical problem with my 1994 C280. When you hook up the battery, the entire dashboard lights up without the key in. When I try to turn the ignition with the key in it, nothing changes. The car doesn't start either. I replaced the ignition switch which didn't help, disconnected the alarm module assuming that it could be thinking it should be immobolized. I only have the keys no key fob so I cannot try and arm or disarm the car that way.

I checked the fuses under the hood as well as in the trunk and they all in working order. I began pulling relays hoping to find the one which controls the dashboard but I haven't found it.

I saw a post in the DIY Articles section talking about the alarm disablement and it would require placing a jumper on the relay. The unfortunate part, is the article was for a 93 and they moved the alarm module to the trunk in 94 and I'm not sure where the relay for the alarm was relocated to.

Any suggestions or help if you've seen this before would be greatly appreciated. If you need additional details let me know.

Thanks!
Brian

What happens if you remove fuse 3, 7, or 10?

Do the light still stay on with key off?

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Thanks for the response. I went ahead and pulled fuse 3 (automatic climate control) and the dashboard was still lit up. I then pulled fuse 7 (Low beam, left) and it still remained lit. On my car, fuse 10 is vacant. These were in the front fuse box. I went to the one in the trunk and pulled 3 (Seat adjustment, left), 7 (rear window lift), and 10 (front window lift), and the lights were still on the dashboard instrument panel.

What I have done is started looking at what doesn't work (besides not sending any power to the starter to start the car). I noticed the interior convience lights don't turn on nor the light in the trunk. The automatic door locks do not work either. I can put the key in the driver side door and it will initiate rolling up the windows but it won't roll them back down. The other thing I noticed was the horn doesn't work either.

At this point, my assumption it is a relay that is stuck in a closed state. I went through the wiring diagrams last night and the one item that stood out the most when going through the list was the Convience Control Module. But would that cause the dash to light up. Or do I have multiple relays bad?

The other one that stood out was part of the anti theft circuit for the starter lockout relay. From what I read this is in the left kick panel.

Any additional thoughts are welcome.

Thanks!
Brian

I'm looking for the starter lockout relay. I've looked under the passenger floorboard, in the trunk, behind and underneath the radio, removed the center console and looked along side there, pulled up the driver side carpet and looked along the kick plate, behind the instrument cluster only to find nothing.

I just read a posting of another location behind the glove box. Can somebody confirm/deny for a 94 C280? I really don't want to continue pulling more things out only to discover nothing.

I know there are the 5 pin relays behind the fusebox in the engine compartment but I'm assuming those are for other items.

Since it is late, I won't be able to work on the car until tomorrow evening. If someone could reply with other possible locations I'll look at those tomorrow.

Thanks!
Brian

As I began to trace wires through, I decided to pull the fuses panel out of the plastic holder. I found Relay B (which is a K38 5 pin relay) had corroded and melted wires all the way up. As I began to pull the wires back, I found the wires have damaged the loom going behind the engine. This would explain all the power issues.

I need to know if part of the wiring loom can be purchased or if it is a all or nothing? I saw where you can buy part of the engine wiring loom but not part of the rest of the loom. I'll probably just splice in new wires if I cannot buy just a section.

Thanks!
Brian

I would just slice if I were you. Dunno the answer to your question

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