relay on radiator fans

Clipped · 8th May 2008, 07:07 AM

i need to wire up my radiator fans directly...because of air conditioning problems.

is the 30 amp bosch relay up to the task of running 2 electric radiator fans?

the stock relay doesnt say how many amps it can handle.

DigitalJunkie · 8th May 2008, 07:16 AM

I would probably use 1 relay per fan. The start-up surge of the motors can be fairly high,though it is pretty short.

jol50 · 9th May 2008, 02:16 AM

Some cars have multi speed fans, low for AC in traffic and high for when car gets too hot I think it is. If you are into that stuff you can swap one into there. If yours runs real hard when on, they really suck on the alternator if you run them all the time. Or maybe a large resistor of some kind to slow it down.

I Am An Idiot · 9th May 2008, 06:01 AM

if the turn on surge of both fans at the same time is a bit much for your electrical system, you can build a simple delay circuit with a resistor, and a cap to delay the second fan until after the first one has started.

Clipped · 11th May 2008, 06:21 AM

good ideas... my radiator busted and the fans wouldnt turn on, the culprit was the plugs that actually plug into the fan...so i wired some connectors straigt to the plugs and dropped glue inside the housing to secure it.

but i still went ahead and hard wired a relay to the fans to turn them on...i think i may even have a counterfeit relay... there are two '87' terminals...no 87a...and they both come on at the same time regardless.

right now i have one relay powering both fans but will add another relay just for safety precautions.

8th May 2008, 07:07 AM	#1
Clipped diyAudio Member Join Date: Mar 2005 Location: home	relay on radiator fans i need to wire up my radiator fans directly...because of air conditioning problems. is the 30 amp bosch relay up to the task of running 2 electric radiator fans? the stock relay doesnt say how many amps it can handle.

9th May 2008, 06:01 AM	#4
I Am An Idiot diyAudio Member Join Date: Mar 2007	if the turn on surge of both fans at the same time is a bit much for your electrical system, you can build a simple delay circuit with a resistor, and a cap to delay the second fan until after the first one has started. __________________ If it ain't broke Don't fix it

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8th May 2008, 07:16 AM	#2
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	I would probably use 1 relay per fan. The start-up surge of the motors can be fairly high,though it is pretty short.

9th May 2008, 02:16 AM	#3
jol50 diyAudio Member Join Date: Nov 2007	Some cars have multi speed fans, low for AC in traffic and high for when car gets too hot I think it is. If you are into that stuff you can swap one into there. If yours runs real hard when on, they really suck on the alternator if you run them all the time. Or maybe a large resistor of some kind to slow it down.

11th May 2008, 06:21 AM	#5
Clipped diyAudio Member Join Date: Mar 2005 Location: home	good ideas... my radiator busted and the fans wouldnt turn on, the culprit was the plugs that actually plug into the fan...so i wired some connectors straigt to the plugs and dropped glue inside the housing to secure it. but i still went ahead and hard wired a relay to the fans to turn them on...i think i may even have a counterfeit relay... there are two '87' terminals...no 87a...and they both come on at the same time regardless. right now i have one relay powering both fans but will add another relay just for safety precautions.