Browning Posted December 1, 2011 Report Share Posted December 1, 2011 98 neon For the last few years the fan has been rigged with a wire running from it to the ac/heater fuse. Here lately it's been causing problems and last night it decided to melt the fuse, plastic and all so neither the fan nor the heater was working. I'm ordering a fan relay online but need to rig it for the mean time and the fuse hole is burnt on the one it was in so I'm not using that again. For now, it's in a slot named power door locks but the car doesn't have them? My question is, could I just use the wire for the fan relay? Just go back behind the relay and splice it in so it stays on when the ignition is on? I'm thinking this may be better than using a fuse. Quote Link to comment Share on other sites More sharing options...
99FLHRCI Posted December 1, 2011 Report Share Posted December 1, 2011 Fuses are always a good thing. No matter what there is always a "fuse". If you don't put one in, the next weakest point is your fuse. We had a tech at work not put a fuse in. He then used a wire that was just big enough for the current load. The driver applied the brakes triggering the current. At that point all of the insulation melted off the wire and began glowing bright orange. This caught things on fire. His wire was his fuse. Not a good idea. Quote Link to comment Share on other sites More sharing options...
Boydness Posted December 1, 2011 Report Share Posted December 1, 2011 98 neon For the last few years the fan has been rigged with a wire running from it to the ac/heater fuse. Here lately it's been causing problems and last night it decided to melt the fuse, plastic and all so neither the fan nor the heater was working. I'm ordering a fan relay online but need to rig it for the mean time and the fuse hole is burnt on the one it was in so I'm not using that again. For now, it's in a slot named power door locks but the car doesn't have them? My question is, could I just use the wire for the fan relay? Just go back behind the relay and splice it in so it stays on when the ignition is on? I'm thinking this may be better than using a fuse. I don't understand. You could indeed run it so that the ignition hot closes the relay to deliver power to the fan. Assuming a 4-terminal relay: ---IGN hot ---- ground [closes the relay] ---power/battery ---- to the Fan [powers the fan] What are you jumpering? Obviously, the fan or other load on the circuit drew high amperage that caused the melt of the original connector. You will want to fuse the "power/battery" terminal of the relay, although technically it could also be on the "to the fan" side of the relay". The location should be wherever it is easiest to change the fuse. The ignition hot is most likely fused already, closing the relay will not draw much amperage. Additional fusing will just prevent a fire/melt in the event that the ignition hot circuit shorts to ground and draws excessive circuit. Quote Link to comment Share on other sites More sharing options...
Boydness Posted December 1, 2011 Report Share Posted December 1, 2011 98 neon For the last few years the fan has been rigged with a wire running from it to the ac/heater fuse. Here lately it's been causing problems and last night it decided to melt the fuse, plastic and all so neither the fan nor the heater was working. I'm ordering a fan relay online but need to rig it for the mean time and the fuse hole is burnt on the one it was in so I'm not using that again. For now, it's in a slot named power door locks but the car doesn't have them? My question is, could I just use the wire for the fan relay? Just go back behind the relay and splice it in so it stays on when the ignition is on? I'm thinking this may be better than using a fuse. Ok, I re-read it, you want to jumper the fan until you can install the relay. You really do not want to do that, as you have something drawing a high load on the circuit, thus the melt. Maybe, a fan motor that is requiring excessive amperage due to the higher resistance of the motor due to age. Running it straight from IGN hot and fuse-ing it, means that you will need to size the fuse appropriately. A 30-amp fuse does you no good if the wire is going to melt at 20A. If you are really going to run it direct feed from IGN hot, I would start with a small 10A, and gradually work up the amperage of the fuse. I would be guessing the fan is drawing 30A or more to due that amount of damage. The smaller fuse 10A or 15A might allow you to run it for periods of time and safely protect you from a fire. But, you will be changing fuses depending on where the high draw is occurring (ie at start-up or after some point). Even with the relay installed, you have something wrong with the circuit, which is drawing the excessive current. That is going to have to be addressed at some point. Quote Link to comment Share on other sites More sharing options...
ross Posted December 1, 2011 Report Share Posted December 1, 2011 With the way the weather is right now, you can honestly just drive without a fan right now unless you will be in massive amounts of stop and go traffic. That would get you by until you receive the new fan relay. Quote Link to comment Share on other sites More sharing options...
Boydness Posted December 1, 2011 Report Share Posted December 1, 2011 With the way the weather is right now, you can honestly just drive without a fan right now unless you will be in massive amounts of stop and go traffic. That would get you by until you receive the new fan relay. I wonder if the fan is even running, it is possible that it might have seized and that caused the melt. As long as the radiator is free flowing, he should be fine. Quote Link to comment Share on other sites More sharing options...
spectragod Posted December 2, 2011 Report Share Posted December 2, 2011 You will need a fuse, regardless if you use a relay or not. The fuse will protect the circuit from meltdown. There are numerous charts available online that will breakdown the size of wire that you will need, dependent on the run length and the current draw of your device. Quote Link to comment Share on other sites More sharing options...
Boydness Posted December 2, 2011 Report Share Posted December 2, 2011 The entire circuit needs to be addressed or there is sure to be future melt. The OP said that it ran like that for years before the melt. I am assuming that the original relay was bypassed and the rigging ("with a wire running from it to the ac/heater fuse") lasted a fairly extended span of time, the extent of the melt is obvious that something changed recently. Replacing the relay is only part of the solution, whatever created the excessive draw is will still cause the same draw of amperage on the new wire/fuse. Monitoring the circuit and watching the amount of draw at different points should point to the cause. Most OEM relays are sized to be appropriate for the engineered load and just slightly more for protection. The excessive draw might be out of tolerance for the relay and cause the relay to fail/melt. It would be a shame to waste the money on having to order another replacement relay... Definitely, verify the max amperage rating for the relay and verify that the circuit is fused correctly (which should be less than the maximum of the relay). A 30A relay should have a 25A fuse; A 20A relay would have a 15A fuse; etc. Fuses are cheaper than relays. Quote Link to comment Share on other sites More sharing options...
Green Bastard Posted December 3, 2011 Report Share Posted December 3, 2011 try taking the power wire and putting it directly on the battery + and see if the fan even works, if the fan motor seized then it would cause a very high amp draw and cause the meltdown you experienced (not saying that was in fact the cause, just a possibility) only do it for a second or two just to see if it works. if it does the cheapest way i can think of to make it work would be to get a universal 4 pin relay from the auto parts store and an in-line fuse.. the relay should have one constant power, one ground, one acc power and the power wire for the fan, the way it should work is the acc wire works a switch inside the relay when the key is turned on to make the connection for the fan, i would put the fuse in the line going to the fan. that would be a permanent fix though Quote Link to comment Share on other sites More sharing options...
Browning Posted December 4, 2011 Author Report Share Posted December 4, 2011 still haven't ordered the relay. Still have it rigged to the other fuse slot and it hasn't given any problems so far. Might just leave it since the slot doesn't seem to be used for anything else like the other one was. Quote Link to comment Share on other sites More sharing options...
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