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  #121  
Old September 9th, 2012, 09:51
Bjorn86 Bjorn86 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

Ok, first off, THANK YOU for this thread and the diagrams, I would've never figured this out on my own. I've got to admit, wiring is not my thing. After staring at this diagram and the pictures and going through the entire thread about 5 times, I've got the wiring understood.

My question is, does anyone have a suggestion on what brand/part number/type of relay to use that can possibly be found locally at auto parts stores (I've got NAPA, O'reilly, Autozone)? Do I need one with a diode? Heck, I'd like to buy one with the diode just in case there is a chance it may make a difference. Any amp/volt minimum requirements? I'm looking online and there are a bunch of different ones.

I really need to do this on my 99 after my cooling issues surfaced this past weekend on the trail. Thanks in advance for any help, and again, thank you for the great thread!

Last edited by Bjorn86; September 9th, 2012 at 10:01.
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  #122  
Old September 9th, 2012, 11:06
CobraMarty CobraMarty is offline
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Re: Radiator Fan Override Switch (The Easy Way)

Thanks, that helped. I can use a turbo timer to activate the relay.
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  #123  
Old September 9th, 2012, 18:58
DanMan2k06 DanMan2k06 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

Truth. I forgot a ton of turbo cars have a very similar setup.
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  #124  
Old September 11th, 2012, 13:08
fyrfytr1717 fyrfytr1717 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

Quote:
Originally Posted by Bjorn86 View Post
My question is, does anyone have a suggestion on what brand/part number/type of relay to use that can possibly be found locally at auto parts stores (I've got NAPA, O'reilly, Autozone)? Do I need one with a diode? Heck, I'd like to buy one with the diode just in case there is a chance it may make a difference. Any amp/volt minimum requirements? I'm looking online and there are a bunch of different ones.

12 Volt 20-40 Amp is typically what you're looking for, however I've never had much luck finding relays at the local auto parts places. Maybe I just haven't tried hard enough? Maybe I just need to bring them a part number from an application I know is correct? I don't know... I usually order mine from Susquehanna Motorspots. Here's a very helpful page on their website in regards to picking out the right type of relay for your needs.

http://www.rallylights.com/hella/Relays.aspx

The HL87104 is the relay w/ diode that I usually use. It can be used NO (Normally Open) or NC (Normally Closed) so it allows for some flexibilty in that regard. For lights (or other things that are typically activated in pairs) I like to use the HL87483 because it has dual outputs. There are a few dual output options available, but I like this particular one because it has no mounting bracket which save me from having to cut the brackets off. Between these two relays, I have all my add-on circuits covered. They can even replace most of the factory relays as well. I just keep a spare or two of each one on hand.

If you want to mount them as seen in my pictures, use them in conjunction with the HL87123 Mini Relay Base w/ terminals.
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  #125  
Old September 11th, 2012, 18:09
Bjorn86 Bjorn86 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

Thank you, I couldn't find anything at the parts store!
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  #126  
Old September 23rd, 2012, 12:27
Bjorn86 Bjorn86 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

STUCK, PLEASE HELP!
Again, I am a complete newbie when it comes to wiring. I want to use an illuminated rocker switch for this. The original wiring diagram posted by fyrfytr1717 looks like it shows a switch with only 2 terminals, whereas the lighted switch has 3. I think I've got it figured out, I just would like some confirmation before I do it:

Terminals on back of switch:
1) + (I'm thinking the DB/PK coming from PDC)
2) LOAD (New 18 gauge wire to Pin 87 of the relay)
3) - (Ground wire to a ground location)

I'm hesitant to do this because in the original diagram, there is a wire running straight from PDC to Pin 87, with a switch spliced into that. The way I'm thinking of doing it, the wire from PDC would go straight to the switch, then back out of the switch to Pin 87. Is this correct?
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  #127  
Old September 24th, 2012, 01:03
fyrfytr1717 fyrfytr1717 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

You're actually going to have to disregard the labeling on the back of the switch because in this particular circuit, you are switching the ground as opposed to the 12V+. Without doing a continuity test on the switch I can't tell you for sure, but I would assume you have to do the following...

1) + Hook up to ground (chassis or other nearby ground wire)
2) LOAD Hook up to new wire leading to Pin 87 of the new relay and DB/PK wire connected to the original Fan Motor Relay in the PDC
3) - Hook up to a 12V+ source for the illumination (I'd recommend an ignition switched one to keep from accidentally draining your battery)

I know it sounds backwards, but you want to pass the - through the switch and out the load terminal. In this particular case the + is only use to illuminate the indicator light. The one catch here could be if your switch uses an LED for light. Incandescent bulbs don't care which direction the electricity is flowing so reversing the terminals as I described above is just fine. LEDs on the other hand will block electricity flowing in the wrong direction which will keep the light from turning on...
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  #128  
Old September 24th, 2012, 07:54
Bjorn86 Bjorn86 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

That makes sense.....thank you! For the 12V source for illumination, can I just use the same DB/WT wire?

Does that go the same for a simple unlighted SPST toggle switch, + will be grounded to chassis and the - will go to the wire runnning to pin 87?

Sorry if these questions are ridiculous, but I'm clueless about wiring, just wanting to learn!

Last edited by Bjorn86; September 24th, 2012 at 08:02.
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  #129  
Old September 24th, 2012, 15:06
fyrfytr1717 fyrfytr1717 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

Quote:
Originally Posted by Bjorn86 View Post
That makes sense.....thank you! For the 12V source for illumination, can I just use the same DB/WT wire?

Does that go the same for a simple unlighted SPST toggle switch, + will be grounded to chassis and the - will go to the wire runnning to pin 87?

Sorry if these questions are ridiculous, but I'm clueless about wiring, just wanting to learn!
I think the DB/WT wire should work fine. I don't know where you're mounting your switch, but if it's in the dash area, another option would be to track down the orange dimmer wire that runs to all the factory indicator lights on the dash and center console. This would cause the illumination on your switch to dim with the cabin lights instead of being full intensity.

For a simple two terminal SPST toggle switch, it doesn't matter which terminal you use. It merely makes and breaks a connection inside the switch and doesn't care about which direction the electricity is flowing.
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  #130  
Old September 30th, 2012, 16:19
Bjorn86 Bjorn86 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

Quote:
Originally Posted by fyrfytr1717 View Post
Glad it worked for you! It seems the DB/White wire in the small loom may be a better choice for those attempting this mod. Easier to find, less chance of a mix up, and I'm thinking it is actually the wire that pin A2 on Connector 1 is directly attached to.
I just finished wiring this up on my 99 and it works flawlessly! Thank you very much to everyone who contributed to this thread. I also used the DB/WT wire in the small loom and it seems to work as described.
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  #131  
Old October 1st, 2012, 01:34
fyrfytr1717 fyrfytr1717 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

Excellent! Congratulations on tackling a mod that was out of your comfort zone and following through with it to a successful conclusion. Hopefully you learned a little something in the process...
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  #132  
Old October 1st, 2012, 06:49
CobraMarty CobraMarty is offline
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Re: Radiator Fan Override Switch (The Easy Way)

OK, so this way give you a switch to manually turn the fan on and off anytime, engine running or engine off.
No automatic turn on or timer to shut off when you turn off the engine and walk away from the vehicle.
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  #133  
Old October 1st, 2012, 23:40
fyrfytr1717 fyrfytr1717 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

Not exactly, it will only work while the ignition is in the RUN position (regardless of whether the engine is running or not) as the factory fan relay uses a ST-RUN source as opposed to a constant hot. The first wiring diagram I provided only allows you to force the fan to turn on. The second wiring diagram allows you to override the PCM and force the fan off as well. You are correct that there is no automatic turn on or timer delay in this particular write up. There is another thread that covers that...
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  #134  
Old December 15th, 2012, 08:20
BoulderXJ01 BoulderXJ01 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

Quote:
Originally Posted by fyrfytr1717 View Post

As for your fix solving the CEL issue, I can only figure that either you were using the wrong DB/WT wire (which incidentally is "there and not" while the ignition is on) or the integrated diode in my relay is preventing the CEL. I'll have to try putting in a normal relay and see if it causes a CEL to find out for sure. To make sure you were using the correct DB/WT wire, perform a continuity test with your DVM between it and Pin A2 on Connector 1 in the PCM as detailed in the write up.
fyrfytr1717 - thanks so much for this thread. I'm working on a fan delay timer and your write up was really thorough and has helped me tremendously. I'm having a problem where my timer is acting really strange, the timer seems to loose power randomly. I saw your comment above about "there and not" and was wondering if that was my problem. I grabbed a DB/WT wire from that loom and verified with a multimeter that it was switched 12V, but if it is "there and not" that would totally explain the behavior I'm seeing. I did not verify that it was the "correct" DB/WT wire you identified. Can you elaborate - do you really mean that the other wire turns on and off during operation?
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  #135  
Old December 15th, 2012, 23:42
fyrfytr1717 fyrfytr1717 is offline
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Re: Radiator Fan Override Switch (The Easy Way)

No, in that reply I was just attempting to straighten out some misinformation that had muddied up my write-up. I was only offering up the idea as a possible reason why his "fix" may have worked. I don't however believe that there actually is a DB/WT wire anywhere that is "there and not" while the ignition remains in the run position. The closest thing I can think of was a wire (DB/OR maybe?) that had power intermittently as the A/C compressor cycled on and off. Sorry.
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