! W126 a/c help and relay fire
 

So my AC is low and I decided to fill it up with propane. For the first time ever the electric fans kicked in on thier own. So clearly the system is presurizing better.

But... The compressor clutch stays on full time now. I also had my very first under-hood fire! Can now join that club! Is that relay, under the booster, related to compressor clutch or fan control?

I would search for help in old threads, but I am on my phone with no net around. And with the car behaving this way, I don't want to drive it much. BTW, pressure readings look fine. And if you question the use of propane, google it! Thanks.

I assume you applied a sticker to your car that says "attention all!! my car is a rolling bomb! stay away.

Seriously though, I've used Duracool pretty successfully on the 84 300SD. Anyone know if Duracool is just propane packaged more expensively?

That is the blower motor resistor and is a common fire spot.

Really? Odd that I had no prior smoke issues until today. I keep it very clean in that gutter because of the known fire issue. Today it was just a couple leaves. Think I may re-locate it.

Just happened to me today , I saw the leaves down there which I will vacuum out. I think that the resistor is fine, it's the leaves that catch fire.

By "stays on full time" do you mean when the temp switch calls for heat? My compressor on my 126 stays on unless it is in heat mode.

This is the exact issue that occurred.

Ok, compressor clutch is fine. Once I dropped to low fan, it cycled normally. I guess I am just used to system cycling more.

As for the fire. I sure do keep it clean down there. One of those flex extension grabbers works great for getting leaves (and screws) out of tight places.

I still think I will re-locate it. If it can generate enough heat to combust leaves then over time it can not be good for the cables above it.

Yes, I just commented on this yesterday in another thread. Since the weather is heating up, I am reading more of this, as more people are restoring and cranking up the A/C.

Last summer we charged up the A/C on our W126, we had the A/C on high and I started smelling "hot" leaves. No smoke, but I knew what was going on, so we shut it off and I vacuumed out all of the leaves, all was fine.

A/C leaked down some over the winter, so we recharged yesterday - still not blowing ice cold when idling, but guess its normal for an old car like this. Again, started smelling leaves. This time could not find the vac cleaner end to get in there, so this evening I hooked up the air compressor and blew all of the leaves and pine needles out of there. I dont know how so many accumulate in there in one year, but they do. Very bad design, I dont know why Mercedes didnt recall and reposition this somehow.

Now I am also reading of these cars not only catching fire because of leaves, but I have been reading where it says the "blower fuse holder" catching fire, not sure exactly where this is and why they catch fire?

The blower fuse is above the relay on the top backside of the false firewall. It's a long small black box.

here's where my fuse is.... the one that burned out on Saturday. thought my car was on fire!!

Thats a very different fuse than mine.

my car is 86 560SEL. think it was a dealer recommended item to be added... probably by 91 they figured out they needed the fuse and put it there from the factory.

Yeah, the one on our '88 300SEL looks different as well.

Well we had A/C most of the trip out today, then it stopped working. :( Gonna start a new thread.

That certainly is not a dealer item. Looks like a hack job, you may want to look into that more.

'87s have the larger fuse for the blower fan external factory, I think my old '86 420SEL did also. My '85 300SD did not.