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Engine Cooling Fan

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SuperCB	Engine Cooling Fan	Lead	[-]
Posts: 682 (05/05/2008 10:30 AM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Tags : None Does anybody know the operation procedure of the engine cooling fan? I know it is supposed to stay on when the A/C is on, but how about when you are defrosting? I would imagine it would cycle as needed according to the engine temp? When you turn off the A/C and go to defrost, should the fan stop right away? Or stay on for 5 minutes? That kind of thing. The reason I ask is because I was driving around on Saturday doing my chores (A/C on low), and my cooling fan fuse (30amp) blew; the fuse melted and has a hole in it (I replaced the factory fusible link with this fuse two years ago). After changing the fuse, I cycled the fan; it would come on when I turned the A/C on, but wouldn't turn off when I switched to defrost. If I shut the car off, then re-started while on defrost, the engine fan would not come on. I am concerned that I may have a cooling sensor issue, or something else related that is causing the fans to stay on, or not operate like it should. Also, has anybody re-wired their fan to stay on for a certain amount of time after the vehicle has been shut off? I would imagine a simple "timer relay" would do this. Forgot to mention that the car is a '90 SC, auto and blue if it makes a difference. Chris B Last Edited By: SuperCB 05/05/2008 10:37 AM. Edited 2 times.
vtgecgrs		#1	[-]
Posts: 1182 (05/05/2008 03:58 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Chris, On my car the fuse for the fan is 80 amps from factory and mine melted down too. I'd check the current draw of the fan motor it could be drawing excessive current. I am quite sure the 80amp fuse size is due to the in rush current draw when the fan first turns on but I have found 35amps when the fan is just running on high speed. I have melted down 30amp rated wiring and fusing in a similiar curcuit for my fan and that is what prompted me to check current draw. The largest 12v relays I have found are only rated at 40amps too. John
5LCougar		#2	[-]
Posts: 2449 (05/05/2008 06:02 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	The Cooling fan will come on, and cycle whenever the A/C pump is turned on The Fan will stay on for like 15-20 seconds after the AC pump disengages just incase it engages again in that time...) (this is also taking effect you AC system is full and in working order) NOW the AC system will turn on In the MAX AC, AC, FLoor Defrost and Defrost selection (and if you have a '94+ Floor/Vent aswhile) If you turn on the AC and getting the fan going, then shut off the HVAC system Does the Fan come to a stop withing 30 seconds??? and when you turn off the car in Defrost, and then restart it, does the fan come on at all or the AC pump cycle?? Oh and i'm with John, 30amp is alittle small.. 70-80amp Minium would be the choice thing.. It's what i'm using on my M8 E-fan on my '91, along with 8ga wiring, a `softstart' Relay (AKA Flex-a-lite VSC since i have to yet to get it to work by itself, i have another Adjustable fan switch `manually' turning it on) "Turning seems to be a lost form." "you shouldn't drive faster than your guardian angel can fly" Last Edited By: 5LCougar 05/05/2008 06:05 PM. Edited 1 times.
SuperCB		#3	[-]
Posts: 683 (05/05/2008 07:24 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	I know we discussed draw a few years ago when I thought the fan motor went, and it turned out to be the fusible link. I tested the draw at start up, and it was 24-26 amps, then went down to 17-18amps. Based on this, I figured a 30amp fuse would be adequate. Also, the wiring for the motor isn't that large. It is no bigger than 10ga. The A/C is working as it should. I just went and did a few time tests; the motor stopped after turning off the HVAC in 40-60 seconds. When I turn the HVAC back on, the fan starts within a few seconds. The wiring where the fusible link was is 10ga also, but the connector that joined it to the harness looks a lot smaller. Maybe I will grab a maxi-fuse holder, loose that connector, and get a 70-80amp maxi-fuse. I guess that 30amp fuse was hanging on for dear life over the past two years. Chris B
vtgecgrs		#4	[-]
Posts: 1185 (05/05/2008 09:59 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Chris check and see what the rating is on the wire first. What typoe of meter were you using I had to borrow a fluke clamp on from work as I was getting fluctuating readings with my $100.00 meter and there was a big difference. Kevin where are you getting the 80amp curcuit? I need one and have not found one yet. Chris can you provide something like that a relay and switch rated at 80amps? John
5LCougar		#5	[-]
Posts: 2451 (05/06/2008 05:49 AM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	For me: Fuse is a AGU Glass Fuse rated at 80amps (IE `Car stereo' ) Fuse Holder is in a 4 gang AGU Fuse Holder (IE `Car Stereo', and is holding fises for my stereo and Headlights) Wireing is 8ga `car stereo' wiring too.. the rest is self explanatory i thing (OH i was using a 70amp Hella Relay for awhile before i got the FLex-a-lite VSC) Also the Mark 8 Cooling fan is known to draw up to 80amps on start up.. the MN12 Fan i was using too, not as much, no one i think has `tested' it, but i think if i remember reading it's like 50-60 if started on High?? (Mine started on Low then went High to releieve strain on the Electrical system) "Turning seems to be a lost form." "you shouldn't drive faster than your guardian angel can fly"
SuperCB		#6	[-]
Posts: 685 (05/06/2008 08:36 AM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	vtgecgrs said: Chris check and see what the rating is on the wire first. 10ga is good for about 40-50 amps. Is there more that I need to know? vtgecgrs said: What type of meter were you using I had to borrow a fluke clamp on from work..... Not sure what type. My buddy is a mechanic, so probably Snap-On or some other hi end meter. vtgecgrs said: Chris can you provide something like that a relay and switch rated at 80amps? I've never seen a relay rated that hi. I'd go to a solenoid, Cole Hersee or similar; same as a starter solenoid, but continuous duty. I use a few of them; one on the truck for the dual batteries, and one in the car for the auxillary fuse block. Chris B
vtgecgrs		#7	[-]
Posts: 1187 (05/06/2008 04:47 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Chris, Do not put a fuse higher than the wire rating or you could have an electrical fire instead of just popping a fuse. I looked at a package of 10awg wire at canadian tire today and it shows 30 amps on the package. It is a standard rw90 stiffer wire so if the wire going to the fan is more flexible it will likley be rated higher, finer twisted wires are typically suitable for a higher rating, but that will vary depending on the design of the cable. I am quite sure you have access to decent wire through work so you might want to replace it if you are not sure. I would definatley not go higher than a 50 amp fuse on the stock wire. The cec book shows 30 amps based on a 90 degree c wire. Glad to here you had access to a good quality meter, just making sure, were those readings for low speed or high speed as that could be the difference as the motor should draw more current on high speed. Thanks kevin for the ideas I was going to just pick up a relay and have the ircm turn the relay on, I think I can get one through eecol electric but I'll have to put it in a weatherproof box to protect it. A solenoid might work though I did not think of that. John
SuperCB		#8	[-]
Posts: 686 (05/07/2008 12:25 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	vtgecgrs said: Chris, Do not put a fuse higher than the wire rating or you could have an electrical fire instead of just popping a fuse. No worry's there, John. I may be slow, but I do know a good amount about electrical fires....er.....wait a minute. For now, I'm going to leave the 30a fuse in there and keep an eye on it. There is now a pack of 30a fuses in the door, just in case. Glad to here you had access to a good quality meter, just making sure, were those readings for low speed or high speed as that could be the difference as the motor should draw more current on high speed. I'm not sure. After seeing all the numbers you and Kevin have posted, I'd wager that it was low speed. Thanks for the help guys. Chris B

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