Cool Harness - Anybody here use one?
 

Has anybody here had experience with user -JimF's- "Cool Harness" product. I am looking to put one on my '95 E320. Please advise.

I just received mine in the mail today, but I had plans tonight so I won't be able to install it until tomorrow. It's supposed to be 90 degrees here tomorrow, so that should provide a great day to test it out. I'll let you know how it works.

I have an older version... made by someone else. Yes, they work.

There is no compatible connector. . .
 

for the E320's of '95 vintage and on. That year MB combined both sensors into a 'square' four (4) pin housing, so my CH doesn't fit this configuration. Also, bad news, there's no mating female/male connector to interface.

But contact Art Dalton. I believe he's familiar with that configuration to see if you can 'bridge' the appropriate pins.

JimF,

Isnt 95 the end of the w124? That's what he has. I thought things changed in 96.

Willy

Ok JimF, I guess I'll have to check around. Not a big deal, it just gets pretty hot here in the summer months, and I thought it might help. Thanks anyways

The new 4 prong sensors were from manufacture date of 9/94 on..prior was the single sensor...
The aux a/c fan resistor of the new sensor will be pins 2 & 3
[ br/yl - bu/gy ].
I have found the resistance of 15-1600 to be best on the 104s... They are avail at Radio Shack [ 5 for 99 cents].
Use metal film only ..

Pu in the Cool Harness Today
 

I found some time this afternoon to install the Cool Harness. Went for a nice long test drive, about 15 miles out into the country and 15 back into the city on the highway. Temp stayed below 100 most of the way, but did get up to about 102 during the stop and go traffic back in. I checked when I got back and both aux fans were running. I can say that overall it ran cooler for a longer period of time, and it peaked less than before. I think I may have some other cooling issues, but overall the Cool Harness seemed to help. BTW, it was a piece of cake to install.

Rich, glad it got there ok!
 

Check your af/water ratio: see Menu #17 for some tips. Currently using 35/65% ratio with MB AF and distilled water.

If you haven't flushed/changed your af, this might be a good time to check it out.

Good idea Jim. I did just have a flush and fill at an inde shop here in town. They were SUPPOSED to use MB AF, but when I checked it this weekend it was green. I believe if it is genuine it would be an orange color. I'll be draining and refilling with the proper ratio of "the real stuff" this weekend. I also wonder if the temp sensor might just be bad. I've noticed that I get up 80 degrees after only about 2 minutes of driving (Before I can even get out of my neighborhood). Thats first thing in the AM after sitting all night. Seems pretty quick to me.

In the past, I might have agreed . . .
 

with you re quick warmup. Before I changed my tstat, it would take a relatively long time to warm up which appeared ok!

But after changing it, you could see that the old tstat would not fully close, open about a 1/8". Thus the engine would take a longer time to warm up: that's maybe ok for SoCal but probably not good for any other place.

The replacement tstat does the same as yours: very quick warmup so don't think there's anything wrong.

But would advise the use of MB af and distilled water if you haven't in the past. Consider a good flush before refilling. And try the 40/60% mix (af/water).

...and oddly enough, when I had the flush and fill a couple of weks ago I also had the t-stat replaced! Sounds like you nailed that one!

I'm going to check the mixture ratio Saturday and see where it stands. I'm also going to call the inde shop and ask about the distilled water. It would not surprise me if they used it. The head Benz guy there seems to be really good. If not, I'll just do it over (myself this time) to make sure it's right.

While we are on the topic, would a shot of Water Wetter help?

BTW, what a great forum! Where else can you get this kind of info? This is like the Master Card commercial:

1993 500 SEL - $17,000
Annual maint........a XXXX-load!
Great information on how to do it yourself...PRICELESS!

Thanks Jim!

Didn't mention anything about . . .
 

Water Wetter but if you have read my page (menu #17), you know I use and recommend it.

Use 1oz per quart (S500 = 16qts) so that means, 16oz, about 1-1/4 bottles. Probably one bottle will be sufficient for your.

And don't forget the distilled water! Sorry to harp on this but, it is probably the most important item. Tap water is what destroys the effectiveness of af. Also plugs your radiator.

Sounds like a plan Jim. Thanks again for all of the great tips!

I'll let you know how it turns out.

new issues
 

JimF,

I did flush and refill with 60% distilled water, 40% MB coolant, and used the watter wetter. I'm still running over 100 when it's hot outside. I've also discovered that I have no heat in the car as well. I followed the tips on your site, and I get these codes from the A/C system:

Codes Meanings
E0 43 A/C system coolant temperature sensor (B10/8), open or short circuit **)
E0 74 Heater supply unit circulation pup (A31m1), open or short circuit *)
E0 75 Heater supply unit circulation pup (A31m1), open or short circuit **)
E0 83 Heater supply unit left duovalve (A31y1), open or short circuit **)
E0 87 Heater supply unit right duovalve (A31y2), open or short circuit **)
E0 99 Auxiliary fan, 1st activation, open or short circuit **)
E1 3 Auxiliary fan, 2nd stage activation, open or short circuit **)

Sounds like the heat thing is from a bad heater supply unit. But what do you think about 43,99, and E1 3? Could I have installed the cool harness backwards?