Burnt down fuse... what is it?

[nishboo]

So my 500E is having issues cooling. When I am on the highway, it seems alright (80-90), but when I am in traffic it can rise above 100. The two fans in the front are not kicking on, so I decided to do some research under the hood. I found the two 30AMP inline fuses to be okay. But I also saw this when I went under the hood.

Any idea what its connected to? What it does? Any idea on its amp rating?

Thanks in Advance!

 

[gsxr]

I'm not sure what that GM-style fuse is for, but it's not related to the twin electric fans. The fans may not engage until ~105°C, so it's possible the electric fans are working normally, IF they turn on low speed after the A/C has been running for a while on a warm day. If the fans don't work with the A/C either... something is wrong.

Your cooling system may be working fine, but it's worth checking out the primary mechanical fan clutch, this is a common failure after nearly 20 years. When the engine is warm (~90C or higher), slowly rev it up in park. You should hear the fan roar loudly to approx 3000rpm. If it does not... the fan clutch is very likely defective and should be replaced.

 

[DerFuror]

The fuse in my '93 is 20Amp (yellow). The Electronics section of the Owner's Bible makes no mention of it. The fuse that Fukashima'd in your car looks like it was once a smaller amperage fuse.

Since it is a GM style fuse, perhaps it belongs to a circuit particular to the North American market? Maybe one of our European members can confirm if the fuse exists on their car also?

 

[gsxr]

My 92 does not have this fuse at all.

My 94 and 95 both have a 7.5A GM-style fuse on the passenger strut mount, not the driver side. It's marked "Tel." and apparently is for the factory cell phone. It definitely shouldn't be a 20A fuse though.

Maybe the driver's side location was a 1993-only thing...? Nishboo, what year is your car? (Hint: It helps to put that in your signature, or at least in your profile, along with your location/country).

 

[2phast]

I have this on my 93.5 500e. It should have a plastic cover on it.

You can barely see it in this picture.

I don't remember if this particular fuse burned out on me or if it was another one. One of these controls the AC system.

 

[nishboo]

Yes. Thats the one 2Phast!

Anyways, bought a new fuse holder and ended up changing it. It works!

The reason I know this is because the 2 aux fans in the front started to cool the car, before they didnt. They wouldnt even turn on! So let that be a clue to helping you diagnose fans that dont work. Put a 30A Fuse in it FYI.

The car is a 1993 500E Hammer in White / Grey with 104k Miles. I am in Orlando, FL. I will post pics soon

 

[gsxr]

That is really bizarre. My 92, 94, and both 95's do not have this fuse at all. It makes sense that my 94/95 models don't have it, as the fan wiring completely changed from 94-up, but I can't figure out why it's missing from my 92. Hmmm.

I don't think putting a 30A fuse in there is wise, but hey, it's your car. I poked around the EPC and found something that looks like it may be this fuse, if so, spec is 15A, not 20A or 30A (see Group 54, subgroup 121, callout 421, 424, 427). It appears to be for the low-speed fan only, not high speed... the (second) external 30A flat/strip fuse is for the high speed. If your fans started working again, it's only being triggered on low speed by the AC refrigerant pressure. High speed doesn't kick in until coolant temp hits 107°C (assuming you don't have a CoolHarness­™ installed).

Thanks for updating your signature, btw - looking forward to pics!

 

[DerFuror]

My fuse holder is manufactured by KBR. Part number is 161 937 501. VW/Audi markings are on the part.

A search confirmed the part is indeed a genuine VW/Audi part which has been superceded by 1H0937530. No additional specs or catalog picture available for visual comparison. The part costs about $4.14 USD.


MB p/ns
Cap: 000 545 89 03
Fuse Box (Aux Fan): 001 545 76 01
Fuse 15A: 002 545 10 34

 

[nishboo]

Okay, I will update it to 15A... Didnt know, so i gave it 30A... Thanks for the heads-up!

 

[MDA]

That is really bizarre. My 92, 94, and both 95's do not have this fuse at all. It makes sense that my 94/95 models don't have it, as the fan wiring completely changed from 94-up, but I can't figure out why it's missing from my 92. Hmmm.

The plot thickens...

Having nothing better to do, I just took a look under the hood to see if any fuses were mounted on the driver's side strut tower. And what do ya know... this car does have a covered fuse holder in that location. It's a bit hard to see in pic but it contains two spots for fuses: the one on the left is empty and the one on the right has a red 16A fuse of the same type found in the fuse box just above and to the right of this fuse block. The last image is of the fuse holder itself which plugs into the strut tower mount and shows a 201 part number.

The car is a '94 E500 with a production date of June,1994.

Mike

 

[gsxr]

Having nothing better to do, I just took a look under the hood to see if any fuses were mounted on the driver's side strut tower. And what do ya know... this car does have a covered fuse holder in that location. It's a bit hard to see in pic but it contains two spots for fuses: the one on the left is empty and the one on the right has a red 16A fuse of the same type found in the fuse box just above and to the right of this fuse block. The last image is of the fuse holder itself which plugs into the strut tower mount and shows a 201 part number.

The car is a '94 E500 with a production date of June,1994.

Yup, I should have clarified... we were wondering about the single GM-style fuse holder only. It seems to be only used on the 1993 (and some 1992?) with a 15A GM-type fuse on the driver's side. (??)

The double fuse box shown in your photos (which holds two Euro-style fuses) is likely present on all years of E500E... the one fuse is for the seat heaters, the other is for the factory cell phone. I suspect they moved the phone fuse out of this box and over to the passenger side (as a GM-style 7.5A fuse) starting in 1994 model year, but I'm not positive about that.

 

[MDA]

Got it, thanks. Still scrambling to get my level of knowledge up on all the various doo-dads scattered throughout this car.

So... is that big plastic-clad, metal thingy to the left in these pics the engine???

 

[nishboo]

Updated to a 15A. Car runs great. Fans work perfectly! Thanks for the help guys.