w115 Heater Fan issues

1968 - 1976: 220, 220D, 230, 230.4, 230.6, 240D, 250, 250C, 250CE, 280, 280E, 280CE, 300D
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Jake
170s
Posts: 188
Joined: Wed 28 Dec, 2011 6:06 am
Model you own: w115
Location: Canterbury NZ.

w115 Heater Fan issues

Post by Jake » Wed 06 Dec, 2017 7:43 am

1976 w115 300D .

Heater / A/c fan system has stopped .

There were a couple of times is was sketchy on start up , then just no go.

No previous noises from the fan.

I was imagining mortgaging my soul to buy a new heater fan , then I discovered , there is another fan for the AC , and some interaction between the two and the switching stuff .

All very confusing for me .

What I want to ask is, what do I test , and how , and where .

All thoughts gratefully received .
There is a fine line between hobby and mental illness .

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Bartman4800
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Model you own: w111
Location: Perth WA

Re: w115 Heater Fan issues

Post by Bartman4800 » Wed 06 Dec, 2017 10:24 am

First things first.

Have a look at your fusebox

Replace all aluminium fuses with the correct copper fuses. They are know to corrode (galvanic corrosion due to dissimilar metals)
Clean up the fuse terminals with a bit of scotchbrite cloth.

If you are sure the fuses are all ok, you can look onwards.


Bart
1963 220 Sb Sedan "Kermit" (Australian Assembly)
1960 220 Sb Sedan "Zum Schlachten" (Early German Assembly, with a torsion bar spring for the bonnet) - Stored in Country WA
1981 Subaru Brumby 1.8 with Weber and 5-speed box "little utie" - Sold to another enthusiast!
2006 Ford Focus "missus car"
2002 VW Passat V6 30V Station Wagon (my new commuter bus)

Jake
170s
Posts: 188
Joined: Wed 28 Dec, 2011 6:06 am
Model you own: w115
Location: Canterbury NZ.

Re: w115 Heater Fan issues

Post by Jake » Thu 07 Dec, 2017 11:44 am

Thanks for your suggestion Bart , yes , the fuses all appear good , I did replace them with brass about 10yrs ago when I woke it up from its pre purchase 12yr slumber party . But I have rechecked them again today.

So I fluffed around with a meter today , not really knowing what I was looking at , but I found it interesting that the 2 wires that connect on the insulated junction box on the compressor , have no resistance to earth ?

I have also found a couple of heater fans in the shed, that have resistor boxes attached , both fans work on 12v , but neither box works thru the resistors ? one box has both contacts open , the other box has both contacts closed . Something odd is presented here .
There is a fine line between hobby and mental illness .

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Tony From West Oz
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Posts: 3095
Joined: Mon 20 Jun, 2005 10:04 pm
Model you own: w202
Location: Bedfordale WA

Re: w115 Heater Fan issues

Post by Tony From West Oz » Thu 07 Dec, 2017 9:38 pm

Jake wrote:
Thu 07 Dec, 2017 11:44 am
Thanks for your suggestion Bart , yes , the fuses all appear good , I did replace them with brass about 10yrs ago when I woke it up from its pre purchase 12yr slumber party . But I have rechecked them again today.

So I fluffed around with a meter today , not really knowing what I was looking at , but I found it interesting that the 2 wires that connect on the insulated junction box on the compressor , have no resistance to earth ?

I have also found a couple of heater fans in the shed, that have resistor boxes attached , both fans work on 12v , but neither box works thru the resistors ? one box has both contacts open , the other box has both contacts closed . Something odd is presented here .
Are you saying that the resistance is 0 ohms or infinite resistance?
Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

'83 W123 300D 325000km (Wife's car Josephine - sold).
'84 W123 300D replaced good OM617 912 with OM617 952 and enjoyed having good acceleration for the first time since first driving a 300D in 2002 - became engine and trans donor for 300CD Turbodiesel conversion. Now parted out.
'86 W124 300D sold (Wife's old car - sold )
'85 W123 300CD, 275 000km (Fatmobile) rebuilt turbodiesel from previous Fatmobile transplanted into 280CE (occasional tourer)
'99 W202 C250 Turbodiesel (my darling Wife's car - Sold)
'98 W202 C250 Turbodiesel (my car - Sold)
'06 Ssanyong Musso Crew Cab 2WD Ute (OM662 diesel and Auto Transmission)

Jake
170s
Posts: 188
Joined: Wed 28 Dec, 2011 6:06 am
Model you own: w115
Location: Canterbury NZ.

Re: w115 Heater Fan issues

Post by Jake » Fri 08 Dec, 2017 6:01 am

No resistance , like a direct short , zero ohms .
There is a fine line between hobby and mental illness .

Jake
170s
Posts: 188
Joined: Wed 28 Dec, 2011 6:06 am
Model you own: w115
Location: Canterbury NZ.

Re: w115 Heater Fan issues

Post by Jake » Tue 12 Dec, 2017 9:47 am

After following some suggestions of what to look at , without dismantling the car , I spent some time laying on my back , under the dash today .

I fiddled with the green knob and watched the vacuum pod move the rod .

Near by , kinda laying against the steering column , was a device , plugged into the loom , that had a very strange looking curved piece of thin metal attached. It was odd , as it didn't seem to have a function there .

I wondered if it was part of the cruise control stuff ........ but it seemed odd just hanging there .

So I pushed on the curved lever part AND THE FAN STARTED TO RUN. ...................

Then I figured that it was supposed to be attached to the side of the heater duct box . The two hollow brass rivets had sheared the tails off leaving it hanging by the loom.
I fixed it by replacing the rivets with some 3mm x 50mm screws and remounted the device where is was supposed to be .
Now , when the green knob is rotated , the vac pod pulls the lever , actuating the switch and the fan runs , blowing air out the top vents .

This is the aux fan blowing .

Adjusting the heater fan control , it works thru the 3 speeds as desired .

This will give me cold air just as soon as I get an R12 top up . (I checked the service date on the dryer , for when I replaced it and found it was 10yrs ago, time flys when you're having fun) . So I hope to get that sorted this week.
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There is a fine line between hobby and mental illness .

Jake
170s
Posts: 188
Joined: Wed 28 Dec, 2011 6:06 am
Model you own: w115
Location: Canterbury NZ.

Re: w115 Heater Fan issues

Post by Jake » Tue 12 Dec, 2017 9:50 am

I would still like to know if the contacts in the heater fan resistor box should be normally closed or normally open (with no power applied) .
There is a fine line between hobby and mental illness .

Jake
170s
Posts: 188
Joined: Wed 28 Dec, 2011 6:06 am
Model you own: w115
Location: Canterbury NZ.

Re: w115 Heater Fan issues

Post by Jake » Fri 15 Dec, 2017 10:20 am

Initial attempt to top up the gas was unsuccessful, there seemed to be a blockage in the system preventing flow .

I found the expansion valve (under the glove box) and pulled that out , found the wee brass mesh filter was blocked , cleaned that out , refitted the unit , more gas :) :)

COLD AIR , whoo hoo ,, first time in years . LOL , I really should stop procrastinating when things get a bit tricky .
There is a fine line between hobby and mental illness .

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Tony From West Oz
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Posts: 3095
Joined: Mon 20 Jun, 2005 10:04 pm
Model you own: w202
Location: Bedfordale WA

Re: w115 Heater Fan issues

Post by Tony From West Oz » Fri 15 Dec, 2017 4:20 pm

Congratulations!

When dealing with the unknown, it is better to procrastinate a bit while you research the issues, then have a good look at the area were the issue is causing impact. ask for help (someone else may have done it already).
Then you can start cautiously investigating further.
Once you start pulling things apart it can cause the problem to get worse.

Now you have posted the remedy for your problem, someone else (who needs this information in the future) can search and learn the solution that worked for you.
Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

'83 W123 300D 325000km (Wife's car Josephine - sold).
'84 W123 300D replaced good OM617 912 with OM617 952 and enjoyed having good acceleration for the first time since first driving a 300D in 2002 - became engine and trans donor for 300CD Turbodiesel conversion. Now parted out.
'86 W124 300D sold (Wife's old car - sold )
'85 W123 300CD, 275 000km (Fatmobile) rebuilt turbodiesel from previous Fatmobile transplanted into 280CE (occasional tourer)
'99 W202 C250 Turbodiesel (my darling Wife's car - Sold)
'98 W202 C250 Turbodiesel (my car - Sold)
'06 Ssanyong Musso Crew Cab 2WD Ute (OM662 diesel and Auto Transmission)

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