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308 fan switch over-ride switch

Discussion in 'Technical Q&A' started by Doc, Mar 30, 2004.

  1. Doc

    Doc Formula Junior

    Sep 13, 2001
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    Bill Van Dyne
    If one were to install a manual override switch to the fan switch system, what is needed? I assume that an extra wire would need to be spliced into each wire/ connection of the radiator fan switch and each end of the extra wires attached to an on/off switch. Would an arrangement like this allow for normal automatic functioning of the OEM switch, yet allow for a manual override when desired? Also, would a relay or fuse need to be installed as well? If so, what rating? Just curious about this--just in case the OEM switch were to ever fail.
     
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  3. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
    4,358
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    Thats the trick. Only you don't need to splice the wires , just go down to radio shack and get a female to 2 male spade connectors and plug it onto the rad. thermo switch and run a pair of wires into the cockpit and you have it. No need for a fuse because all you are doing is closing the circuit.
     
  4. Doc

    Doc Formula Junior

    Sep 13, 2001
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    Bill Van Dyne
    Steve--I'm aware that I can do that to completely eliminate the OEM switch operation--ie substitute a manual switch instead. But, what I'd like to do is to maintain the operation of the OEM fan switch AND have the option of turning on the fans manually if I see fit. So, in the case in wiring up a manual switch into the OEM fan wiring attached to the rad switch--would that work or would one cancel out the other's operation?
     
  5. seschroeder

    seschroeder Formula Junior

    Apr 25, 2002
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    Steve Schroeder
    Hayden makes a adjustable fan controller (about 35.00) that works well. It is adjustable to turn the fans on from 90 to 210 degress F. Works well on my 308. There is a post about it somewhere.
     
  6. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Jan 11, 2001
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    Bill -- You misunderstood the description in Steve King's post. You don't replace the thermoswitch in the radiator tank with the added manual switch, you connect the (SPST) manual switch across the thermoswitch (that's what the "{1} female to 2 male spade connectors" are for in his description) -- i.e., if either is "closed", the cooling fans relays are closed which then run the cooling fans).

    Another option is to add the manual switch wiring at the other ends of the wires going to the thermoswitch (if it's a more convenient location -- e.g., at the relay panel).
     
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  8. parkerfe

    parkerfe F1 World Champ

    Sep 4, 2001
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    When would you use a manual switch ? If the car is hot enough to need the fans, wouldn't the thermal switch in the radiator turn them on anyway ?
     
  9. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
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    Hans E. Hansen
    My car has this mod. You don't need to run wires all the way forward. The thermo (radiator) switch wires are accessible in and around the relay panel. Just wire the manual switch in parallel to the thermo switch.

    I turn on my fans during city driving during hot weather. Seems to help a bit to do a 'pre-emptive strike' in stop and go driving.
     
  10. Dave

    Dave F1 Rookie

    Apr 15, 2001
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    While this has nothing to do with the switch you speak of,
    my new aluminum radiator w/shroud, fans and thermo wiring kit,
    should have shipped today from Ron Davis Racing.
    I'll be installing it in my 308, and will post pics and full details when it arrives.
    It looks to be a very economical way to replace/modernize the radiator in a 308/328.
     
  11. Doc

    Doc Formula Junior

    Sep 13, 2001
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    Bill Van Dyne
    Dave--how much did the radiator cost you?
     
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  13. Doc

    Doc Formula Junior

    Sep 13, 2001
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    OK, Steve and Steve--I think I get it now. So, with both switches wiried to together, both will work OK--right?

    As another option a mechanic told me about today is to install a Fiat switch which kicks the fans on earlier that the OEM switch. He indicated that he routinely replaces the OEM switches with the Fiat ones for cooler running. They cost about $15.
     
  14. Dave

    Dave F1 Rookie

    Apr 15, 2001
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    If I remember right, the radiator was $269.00...
    But I also had them build a shroud and install dual fans for a total 3152 CFM
    along with the fan wiring kit and shipping,
    it was $737.66
     
  15. Doc

    Doc Formula Junior

    Sep 13, 2001
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    Dave--that sounds like a fantastic price for an aluminum radiator! Is it a bolt in operation, or do you need to modify it in some way for installation?
     
  16. Dave

    Dave F1 Rookie

    Apr 15, 2001
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    It's not standard Ferrari, and I didn't have any brackets attached as I wanted to wait till I roughed it in here before I fabricated brackets.
    It's their basic Chevy style 26x16x3 cross-flow sealed unit with 1.5" in & out.
    While I will have to do some fab work, it should prove to be a much better solution to replacing the stock radiator.
     
  17. f355spider

    f355spider F1 World Champ
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    May 29, 2001
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    The easiest switch to find that will work is for a VW Rabbit. Around $15, and available in two temps, stock (about 190) and about 10 degress F, lower (180).

    Most auto parts have them, but here is a link to a mail order source:
    http://www.ferrarichat.com/partsandservice/308PartsXref/index.htm
     
  18. Spasso

    Spasso F1 World Champ
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    Feb 16, 2003
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    In a word yes. In the event it doesn't, the manual overide is a cheap alternative to getting stranded on a run through the mountains because of a failed 20 year old switch.

    In addition to the switch I also have amber indicator lights next to the switch that tell me that the fan motors are getting voltage through the relays AND fuses which can also fail, again defeating the thermal switch AND the manual overide. If I see the temps go up and no indicator lights come on I can hit the manual switch. If the indicator lights STILL don't light then I know I have a bad fuse(s) or relay(s).

    Good to have a couple of spare Bosche relays around as well as fuses.

    So in a nutshell, an ounce of prevention is worth a pound of (you fill in the blank).

    DJ
     
  19. Spasso

    Spasso F1 World Champ
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    Thanks Dave,
    My thermal switch just puked yesterday and had to use the MANUAL OVERIDE through rush hour traffic coming back from Group 2 Motorsports.:D
    DJ
     
  20. parkerfe

    parkerfe F1 World Champ

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    There is also a 160f VW switch that will work as well. Hayden makes an adjusttable switch that you can buy at PepBoys for $39.00. It allows you to adjust the temp that the fans come on anywhere between 120f and 210f.
     
  21. f355spider

    f355spider F1 World Champ
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    Hey DJ! I was down there this morning, dropping off my 328GTS. Joe mentioned that you and Rob were they getting alignments. I have a leaky CV joint boot, that needs the clamp/band tightened (I think, as the boots are pretty new). They are also going to replace my fuel pump check valve and accumulator if the UPS guy ever shows up to my house today. :(
     
  22. seschroeder

    seschroeder Formula Junior

    Apr 25, 2002
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    Steve Schroeder
    Take a look at /www.ferrarichat.com/discus/messages/256120/286890.html. Has worked well for me on both the Ferrari and Corvette.
     
  23. Spasso

    Spasso F1 World Champ
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    Hope they have your car done by Saturday. Gonna make it?

    Chris did a fabulous job on the 308. It drives way better and steering loads are lighter and more consistent. The last guy really had it HONKED UP!

    Can anybody tell me what year the VW thermal switch is for?

    I will probably go for the 190f so the fans don't run more than necessary. Usually the only time they are required on ANY car, mechanical or otherwise, is when the car is moving less than 30 MPH.
    DJ
     
  24. parkerfe

    parkerfe F1 World Champ

    Sep 4, 2001
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    The OEM Ferrari switch turns the fans on at 86c which is about 186f. So the VW 190f switch would do you no good. The VW 180f switch will lower your temps by 5c to 10c. You can get the two prone switches at :www.eurosportacc.com/thermfan.htm
     
  25. Spasso

    Spasso F1 World Champ
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    Interesting, I could have sworn my book said 190 but now that you mention it the 186/187 degree number joggled some memory. I will definately consider the 180 switch.

    Now, anybody know what year Rabbit that came out of? I suppose a good parts guy could figure it out anyway.

    Thanks, DJ
     
  26. f355spider

    f355spider F1 World Champ
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    All Rabbit and Golf (early) will work. Just make sure it is the two pole design. If you need a year, use a 1978 or 1979.

    Yes, I will get my car back today, for sure. Chris is a great alignment tech, he did my 328 last summer, and my BMW 540 a few weeks ago.
     
  27. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
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    BTW, if you get a rad switch with a cooler rating than your engine thermostat, you might find that the fans are on all the time (when the car is at operating temp). Or, at least, they might cycle more often than they really need to.

    I've got a 180 engine thermostat, 180ish rad switch, and a manual switch. The PO was paranoid about heat.
     
  28. Doc

    Doc Formula Junior

    Sep 13, 2001
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    Bill Van Dyne
    Where is a good, accessible place to run wires through the fire wall in order to install an thermo over-ride switch? Do the wiring harnesses for the lights run behind the wheelwell liners? They seem to disappear somwhere under the front fenders.
     

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