how to tap in the ignition so fans come on when car is on?

[mitch26753]

ok lets start by saying i searched i found alot of fan info, but non really pertained to me! The person before me cut all kinds of wires beacause, well i have no reason why. the fans where hot wired someway to a switch. I tried re wiring them the right way with no success they wont come on. What i want to know. is how do i tap into the ignition so when i turn on the car the one slim 14" fan i have turns on and stays on as long as the cars on? i am unfamilar with this? i know i have to tap into on of the wires in the engine bay fuse box, but which one? the car keeps over heating and i'm not worried about hurting this motor but i am getting ready to swap over the 6bolt and dont want to hurt that. At this time i am also going to put in a new thermostat and radiator cap. any help would be appreciated and pictures would be even more helpful!

 

[freshlane]

Take out fan relay and install jumper wire. It will turn on fan with key in "on" position.

 

[mitch26753]

Take out fan relay and install jumper wire. It will turn on fan with key in "on" position.

i'm kind of confused, i am not real good with wiring. so you mean take out the fan relay. do you mean the radiator fan not cooling fan right? and they have a high and a low setting so which one do i take out? then you mean jump it i take it you mean jump it from the radiator fan relay to where? the ignition relay or what? kind of confused?

 

[mitsocruiser]

one fan should kick on with the a/c the other fan kicks on with temp what the other guy is saying is take the fan relay out and straight wire it it should then kick on with the ignition

 

[mitch26753]

oh so i take the radiator fan relay which one the high or low? when you say jump it do you mean just put a wire so both of slots connect where the relay should be? like i said i dont have much expeirence when it comes to wiring!

 

[eagletalonjohn]

if you have a eprom invest in a tmo or keydiver chip and socket. they have the option to keep both fans on at the same time. its pretty cool. i actually just got one thats how i found out.

 

[Black_Bullet]

A long time ago i did this. Look at the fan near the coolant resourvior,
look were it has a plug that plugs it in. Open the loom of the wiring of that plug, theres a blue and red wire amongst like 3 or 4 others. Splice and tap a wire onto that wire, confirm its the hot wire for the fans. Then run it back into the ign source in the fuse box and it will turn both fans on when the keys on ign, if you just unplug that one fan then just the a/c fan will run or vice versa.
I had my car like that for 2 years. Took longer to warm car up though but it always stayed good temp, engine bay never heatsoaked, now i have a switch.

 

[mitch26753]

A long time ago i did this. Look at the fan near the coolant resourvior,
look were it has a plug that plugs it in. Open the loom of the wiring of that plug, theres a blue and red wire amongst like 3 or 4 others. Splice and tap a wire onto that wire, confirm its the hot wire for the fans. Then run it back into the ign source in the fuse box and it will turn both fans on when the keys on ign, if you just unplug that one fan then just the a/c fan will run or vice versa.
I had my car like that for 2 years. Took longer to warm car up though but it always stayed good temp, engine bay never heatsoaked, now i have a switch.

what do you mean if you unplug the one fan the other will stay on? are you talking about the plug that plugs right into the fan itself? the other method seemed easie just jump the radiator fan relay? why cant i do that?i can find out which wires go to the high radiator fan, wire them to the fan which has two wires(a positive and a ground). I am still confused weather or not ii need to just connect the two sides of the relay or jump a wire from the fan relay to the ignition wire.

 

[mitsocruiser]

just jump the relays don't worry about nothing else

 

[Black_Bullet]

No your fine, do it however you were thinking of doing it, i was just telling you my version.
Im just saying tapping into the blue and red hot wire thats in the cooling fan harness ( near the plug near the coolant resourvoir ) and tapping that wire you just spliced in to a hot on the fuse box ign. source will make both fans come on full blast when the ign is on. Its just one wire ran from fan wire to ign in fuse box. I didnt have no issues with doing that, now i just did a switch though.

 

[luv2rallye]

OK - I've got to step in here. Mitch: I'm one of the electrical guru's on this site and most people are telling you wrong things for two reasons:
1) Your car is a 2g and the relays, relay sockets, relay wires, and fan wires are all different than on the 1g (which the 1g people are telling you about), and
2) You can't jumper any fan relay socket on a 2g because they are supplied by the battery, not the ignition, so the fan would stay on all the time even with the car off.

You must either do:
1) The elegant and more correct way (safer but more work intensive) of leaving the relay in but cutting the fan relay socket's pin 1 wire and connecting the relay socket end of that wire to ground. This uses the relay to provide power assuming the wires are still there at the fan. It means you'll have to unbolt the engine fusebox however to get at the wire (disconnect battery first). Do you have just 1 fan now - the slimline? I'll need to know which side you have it on (driver/passenger) to tell you the proper relay to use and how to wire it.

Added 7/10/08: Another way that doesn't change anything under the hood but provides fan override is shown in post #11: http://www.dsmtuners.com/forums/pro...-issue-plus-wiring-them-up.html#post151319397.

2) (This method deleted as it was too dangerous - luv2rallye 2/2/2008.)

3) The simplist is probably to connect the black slimline wire to ground and the blue one to it's own 30 amp relay which is connected to battery +12V for the fan power and any ignition on source to activate the relay (this source uses very low current so is ok to go through firewall if have to). In fact you could even connect the relay activation wire to the power that comes from the MFI relay with something right in the engine compartment like to the O2 heater power or the MAS power. Here is the type relay to use which you can get at any auto store: Single Pole Double Throw (SPDT), Single Pole Single Throw (SPST) Automotive Relays. I'll tell you how to wire it up if you choose this method.

 

[mitch26753]

OK - I've got to step in here. Mitch: I'm one of the electrical guru's on this site and most people are telling you wrong things for two reasons:
1) Your car is a 2g and the relays, relay sockets, relay wires, and fan wires are all different than on the 1g (which the 1g people are telling you about), and
2) You can't jumper any fan relay socket on a 2g because they are supplied by the battery, not the ignition, so the fan would stay on all the time even with the car off.

You must either do:
1) The elegant and more correct way (safer but more work intensive) of leaving the relay in but cutting the fan relay socket's pin 1 wire and connecting the relay socket end of that wire to ground. This uses the relay to provide power assuming the wires are still there at the fan. It means you'll have to unbolt the engine fusebox however to get at the wire (disconnect battery first). Do you have just 1 fan now - the slimline? I'll need to know which side you have it on (driver/passenger) to tell you the proper relay to use and how to wire it.

2) Connect the black slimline wire to ground and the blue one to an ignition on fused power source of 30 amps or greater somewhere that can handle it (along with it's other loads) and the resulting fan generated noise spikes won't bother these other loads. Good luck trying to find it (especially in the engine compartment). This is a dangerous solution however having all that current not going through a relay especially if you have to go through the firewall for it. Using a relay is a safer and the correct method.

3) The simplist is probably to connect the black slimline wire to ground and the blue one to it's own 30 amp relay which is connected to battery +12V for the fan power and any ignition on source to activate the relay (this source uses very low current so is ok to go through firewall if have to). In fact you could even connect the relay activation wire to the power that comes from the MFI relay with something right in the engine compartment like to the O2 heater power or the MAS power. Here is the type relay to use which you can get at any auto store: Single Pole Double Throw (SPDT), Single Pole Single Throw (SPST) Automotive Relays. I'll tell you how to wire it up if you choose this method.

hello,
well you have help out a great deal, ill tell you that. I think i will go with the second method it seems easier. I am using one 14 inch slimline fan, it has two wires a hot and ground. so if you could go ahead and tell me how to do it that way. by the way, make sure you break it down as easy as you can, cause wiring is not my thing.

 

[luv2rallye]

Sorry but method 2 I decided is just too dangerous for the following reasons:
1) Current is too high to run fan through any wires without it's own relay. Fans MUST always have their own relay.
2) Whatever ignition on fused power source you choose it could a) induce voltage spikes from the fan and possibly cause irratic behavior, and b) any short in the fan circuit would blow the fuse in that circuit and the car would then be diabled, and c) the additional fan load could easily blow that circuit's fuse since it is not rated for more current than what's already on it.

So in the attached pictures I have provided the wiring for method 3 and suggested location for the relay.
Relay info at: Single Pole Double Throw (SPDT), Single Pole Single Throw (SPST) Automotive Relays.
2g item locations at: Virtual Tour of the DSM Engine Bay - Quadrant map.
Disconnect battery while wiring up everything. The non 14 gauge wires can be any size. Solder all connections.
Also read post 15.
Good luck.

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[mitch26753]

Sorry but method 2 I decided is just too dangerous for the following reasons:
1) Current is too high to run fan through any wires without it's own relay. Fans MUST always have their own relay.
2) Whatever ignition on fused power source you choose it could a) induce voltage spikes from the fan and possibly cause irratic behavior, and b) any short in the fan circuit would blow the fuse in that circuit and the car would then be diabled, and c) the additional fan load could easily blow that circuit's fuse since it is not rated for more current than what's already on it.

So in the attached pictures I have provided the wiring for method 3 and suggested location for the relay.
Relay info at: Single Pole Double Throw (SPDT), Single Pole Single Throw (SPST) Automotive Relays.
2g item locations at: Virtual Tour of the DSM Engine Bay - Quadrant map.
Disconnect battery while wiring up everything. The non 14 gauge wires can be any size. Solder all connections.
Good luck.

man that is so helpful! you truely know what your talking about for sure! thanks!

 

[luv2rallye]

Forgot to add 30A fuse to my circuit in post 13. Make sure you have it. Also added another item in list of relay control wire sources.

Just discovered (11/14/2023) that relay pins 85 and 86 should be reversed in case the relay has an internal protection diode. Pin 86 must then have the more positive voltage to keep the diode reversed biased. To test if your relay has this diode see here (3rtd paragraph): https://www.dsmtuners.com/threads/wiring-up-the-rad-and-con-fan.273919/#post-151312548.

 

[wishful_laser]

i read the posts and you are a genuis. could i use this same diagram for my 1g and also the 30a fuse to the battery, could i use the mpi fuse. its 30a or would i have to run another 30a fuse. my battery is in the trunk but the fuses are still in the stock location. the wire from the relay that goes the ign source, could i use the rad fan relay wire that has power to it when the key is turned forward

 

[luv2rallye]

i read the posts and you are a genuis. could i use this same diagram for my 1g and also the 30a fuse to the battery, could i use the mpi fuse. its 30a or would i have to run another 30a fuse. my battery is in the trunk but the fuses are still in the stock location.

You should be able to use it for a 1g although the wire colors may be different for the relay control items listed on relay pin 85. No you cannot use the MPI fuse because a) the extra fan current will blow the fuse since the engine stuff on that fuse can be near 30A and b) any fan wiring short will blow that fuse and thus permanently kill the engine leaving you stranded somewhere. You need it's own 30A fuse to the battery positive. Note you don't have to run the wire all the way back to the battery - just to the battery positive connection to the fusebox that supplies power to all the fuses.

the wire from the relay that goes the ign source, could i use the rad fan relay wire that has power to it when the key is turned forward

Yes just make sure it's the one that goes to the ignition (for 1g: blue with black stripe on radiator relay or blue with green stripe on condensor high-low change over relay), not the control wire (green with black stripe) which will also show +12V with key on when relay is not activated.

 

[wishful_laser]

i hook up my relay according to the diagram minus the hot wire from my fans arent 14g i dont think. the power wire from the battery and the ground wire going to my fans are lil bigger prob 14g. when i hooked up the last wire(tapping the cas red wire)my power wire from my fans started smoking and melting. wtf. what did i do wrong. i even tried using the blue/ black wire from the rad fan relay. same thing. could this be happening cause the wire is not big enough

 

[luv2rallye]

No. You've got something shorting. Try connecting just the fan to the battery to make sure it doesn't have a short. Otherwise you've probably got the power wire to the fan touching metal somewhere. Also you must not have the fuse in there or it would have blown (or it's wired wrong). Try without the fan but keep the fuse installed. Double check all wiring goes exactly as in the diagram (and fuse MUST be the first thing on the battery positive source).