Low Speed Fan Resistor - we need solution
#1402
ebay from uk as I live in Europe, stuff from USA are expensive with shipping and taxes.
I tested new resistor today in the morning in traffic jam (25 min), outside temp was 25 C (77F) and low speed fan kicked in 4-5 times, then when I stopped the car I checked resistor temp by hand and it was around 50-60 C so the aluminium plate with thermal grease helps a lot. So resistor is good, but I found coolant starts leaking from the expansion cap as temp goes above 104 C (219F), and stops after low speed fan cool down temp. Expansion tank and cap is brand new plastic Meyle. Should I add more coolant to mixture to raise boiling point a bit or check expansion cap? Mixture as I remember is -18 C (-0.4 F)
I tested new resistor today in the morning in traffic jam (25 min), outside temp was 25 C (77F) and low speed fan kicked in 4-5 times, then when I stopped the car I checked resistor temp by hand and it was around 50-60 C so the aluminium plate with thermal grease helps a lot. So resistor is good, but I found coolant starts leaking from the expansion cap as temp goes above 104 C (219F), and stops after low speed fan cool down temp. Expansion tank and cap is brand new plastic Meyle. Should I add more coolant to mixture to raise boiling point a bit or check expansion cap? Mixture as I remember is -18 C (-0.4 F)
Last edited by sajtix; 05-23-2017 at 01:18 AM.
#1403
#1404
If your fan is coming on and off when the ac is on and the temp is low and fan control at 1, then your low speed fan is NOT working properly.
It should stay on. Understand? You seem to have an issue with understanding.
The THICKER red wire is the high speed. The THINNER red wire is the low speed.
Understand? You seem to have an issue with understanding.
It should stay on. Understand? You seem to have an issue with understanding.
The THICKER red wire is the high speed. The THINNER red wire is the low speed.
Understand? You seem to have an issue with understanding.
This helps me, as I have not sat down for hours to read 1300 posts about the low speed fan operation. The above post is a lot of help.
#1406
#1408
Thanks all for contributing to this thread. Got the resistor form mouser and low speed fan is working again! Low speed fan now kicks on at 221F and shuts off when temps get back down to 214F, as measured with a scangauge and in line with the bentley manual. No longer are engine temps reaching 234F, which is when the high speed fan kicks on.
Only word of advice i have is for those who have head lamp washers and placement of the resistor. If you're mounting it on the metal bar in the engine bay per the diagram many pages back, make sure it is not in the way of the headlight washer units. I didn't do this, and whacked my headlight washer module loose while closing the hood.
Only word of advice i have is for those who have head lamp washers and placement of the resistor. If you're mounting it on the metal bar in the engine bay per the diagram many pages back, make sure it is not in the way of the headlight washer units. I didn't do this, and whacked my headlight washer module loose while closing the hood.
#1410
#1411
I put the green amazon unit on and it was around 160 F as well. When you think about it, that is not really that much heat and if you have some good heat sink paste you can transfer that to what ever you are mounting the unit too. Would be interesting to test the resistor when it is not attached to anything for temperature.
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nealsmini (08-29-2017)
#1412
See my post #755 and 758 761 763 on currents and power dissipation. I am concerned about that kind of temp on the resistor. Was this measured on a hot day, the engine running and the hood closed. I suspect the temp in that condition will be a good deal higher. Are you running without heat sink?? Not bolted to a metal body part with thermal paste. I went a bit overboard using a computer CPU heat sink and fan mounted in the pocket below the windshield. But I like projects.
#1413
#1414
The low speed fan current causes about 50 watts to dissipate in the resistor. The spec is 1deg C (1.6deg F) rise per watt on a good heat sink for the ARCOL 100watt resistor. So at 160F the motor mount was probably at about 80F. The calculation is: 50watts times 1.6F is 80 deg F rise, subtract that from the 160F measured suggests that the motor mount was at about 80F, this assumes that the mounting is truly flat and all 4 mounting feet are torqued down. Since you do have it on a heat sink you can expect the resistor to always be about 80deg F above the motor mount temp. Lets say you visit the low desert out here in California where I will be next weekend, at 112F ambient air temp the under hood could be 150 or higher, add 80 and you are at 230deg F. The ARCOL power rating derates in a linear fashion to zero watts at 392deg F(200C). That means at 392deg F it can safely dissipate only 0watts, yes no power can be dissipated at that temp. It is rated at 100 watts at 25C (77F). So it hits a dissipation limit of 50watts half way between 77F and 392F, thats 234deg F. So 234 minus 80 is 154deg F heat sink temp for maximum operating point. That may be where the motor mount temp might be in 112deg F weather. Sounds like yours will be ok.
#1415
#1416
Dead Clubman
Well I bridged the red fan wires with an Arcol resistor. Checked my work and had a short on the low speed input now, (was open before) ...good to go, right?
Nope. Even with the AC on Max, the fan wasn't coming on. So I shut the car off and started to check fuses - with a DMM. They all checked good. So I figured I would fire the car back up and let it run for a while and see if the fan comes to life.
No bloody dice. It turned over but wouldn't fire. An exclamation point is now displayed in the steering wheel, and the check engine light stays illuminated. I tried maybe 5 times, no success, and now the battery is dead.
I am at work with no charger. 76 miles from home, Dammit!
Anyway, here is where I put the resistor:
So:
No AC
No fan
No start
Dead battery
I have a Foxwell NT510 on order - should have it by Friday
May have to see if the dealer will take the car back. This is ridiculous.
EDIT: A friend of the neighbor at my jobsite had a battery charger w 10 amp capability. I hooked it to my battery. Came back 40 minutes later, pulled the charger and hit the button - success! It fired up! I packed up quick and headed home, albeit withe windows down, roof open and heater on full blast (defrost). Made it home, left it running, and low and behold the fan (high speed) came on for a bit. Then turned on the AC - Max, and the low speed came to life! Went and grabbed a flashlight to look at the AC compressor, no dice there. Will need to get a clutch coil for it. (I did put some 134a in it, no change)
I then put it on my charger. And had to pick up my daughter for dinner tonight. Checked the voltage of the battery and it was 12.39. Should have been higher. It fired up and I went over to get her. While there I just left it running. About 3 minutes in the car shut off. Subsequent start tries, maybe 4 yielded no love. Put the fob in the slot, hit the button and poof, it started up. (headscratch)
Can a failing battery cause the car not to start?
Nope. Even with the AC on Max, the fan wasn't coming on. So I shut the car off and started to check fuses - with a DMM. They all checked good. So I figured I would fire the car back up and let it run for a while and see if the fan comes to life.
No bloody dice. It turned over but wouldn't fire. An exclamation point is now displayed in the steering wheel, and the check engine light stays illuminated. I tried maybe 5 times, no success, and now the battery is dead.
I am at work with no charger. 76 miles from home, Dammit!
Anyway, here is where I put the resistor:
So:
No AC
No fan
No start
Dead battery
I have a Foxwell NT510 on order - should have it by Friday
May have to see if the dealer will take the car back. This is ridiculous.
EDIT: A friend of the neighbor at my jobsite had a battery charger w 10 amp capability. I hooked it to my battery. Came back 40 minutes later, pulled the charger and hit the button - success! It fired up! I packed up quick and headed home, albeit withe windows down, roof open and heater on full blast (defrost). Made it home, left it running, and low and behold the fan (high speed) came on for a bit. Then turned on the AC - Max, and the low speed came to life! Went and grabbed a flashlight to look at the AC compressor, no dice there. Will need to get a clutch coil for it. (I did put some 134a in it, no change)
I then put it on my charger. And had to pick up my daughter for dinner tonight. Checked the voltage of the battery and it was 12.39. Should have been higher. It fired up and I went over to get her. While there I just left it running. About 3 minutes in the car shut off. Subsequent start tries, maybe 4 yielded no love. Put the fob in the slot, hit the button and poof, it started up. (headscratch)
Can a failing battery cause the car not to start?
Last edited by Jeffair10; 08-30-2017 at 04:16 PM. Reason: new info
#1418
Thanx for the reply. I went and bought a new battery from Napa, exact same model. Installed it and it still just cranks, not even trying to fire.
When I get home from work today, the Foxwell NT510 should be at my house.
Although we are going camping in the Westfalia this weekend, hope to have some time to at least get a diagnosis.
My bet is that it is the low pressure fuel pump, as it runs like a beast, or doesn't run at all. None of the running crappy sans the turbo, unfortunately. It's a 2009 with 100,610K miles, in which the HPFP would be covered. Unless it has replaced already.
When I get home from work today, the Foxwell NT510 should be at my house.
Although we are going camping in the Westfalia this weekend, hope to have some time to at least get a diagnosis.
My bet is that it is the low pressure fuel pump, as it runs like a beast, or doesn't run at all. None of the running crappy sans the turbo, unfortunately. It's a 2009 with 100,610K miles, in which the HPFP would be covered. Unless it has replaced already.
#1419
#1420
From that I understood you were NOT getting low speed fan operation.
So I'm confused.
If you are not getting power steering fan operation, try popping in another fan. I got mine for like $85 oem manufacturer.
Plus if your car is that old it's probably shot like mine was. Could barely turn it with my finger it was so stuck.
Not sure why you can't start your car after disconnecting the battery. It shouldn't be a problem as I've done that a lot and never had that issue. You might have other issues electrically it seems.
So I'm confused.
If you are not getting power steering fan operation, try popping in another fan. I got mine for like $85 oem manufacturer.
Plus if your car is that old it's probably shot like mine was. Could barely turn it with my finger it was so stuck.
Not sure why you can't start your car after disconnecting the battery. It shouldn't be a problem as I've done that a lot and never had that issue. You might have other issues electrically it seems.
#1421
I would appreciate it if someone could shed some light. 2005 MCS all stock, I put in the new resistor and it still overheats at standstills and low city speeds. The resistor gets hot when I start the A/C so I know it's wired correctly and not blown. I am not an electrics guru so any thoughts greatly appreciated..
#1422
#1423
#1424
The way the fans work are one sensor for temperature and another for the pressure in the AC lines. If you are not overheating with the AC on then it would be logical to assume that the pressure sensor is working. You are not getting any blow off only the temperature sensor gets higher? Where on the temp sensor?
Need some more info. Suggest you check out # 0017 of the below post and provide some temperatures. What temperature does the low speed fan kick in? The high speed?
https://www.northamericanmotoring.co...questions.html
Need some more info. Suggest you check out # 0017 of the below post and provide some temperatures. What temperature does the low speed fan kick in? The high speed?
https://www.northamericanmotoring.co...questions.html
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TBeast (10-06-2017)
#1425
No blow off. Temp needle keeps going a bit from north reading where it usually sits, I have not taken temp readings. When the A/C is on the temp gauge is pointing north rock solid.
Point is, nothing changed since I put in the resistor, it's behaving exactly same as before.
I think it is related, my A/C, when on cold, it briefly blows hot air 3-4 minute after I start the car. This happens exactly the same before and after the resistor mod.
Point is, nothing changed since I put in the resistor, it's behaving exactly same as before.
I think it is related, my A/C, when on cold, it briefly blows hot air 3-4 minute after I start the car. This happens exactly the same before and after the resistor mod.