chpspecial Posted January 22, 2011 Report Share Posted January 22, 2011 While tha small amp is a hinderance to the system... There is a bigger issue here and it might be the fans themselves. Do they spin freely, try connecting them directly to the battery. Any weird noises, do the wires get too hot... Quote Link to comment Share on other sites More sharing options...
Cramer Posted January 23, 2011 Report Share Posted January 23, 2011 (edited) How are your fans tuned into the PCM? If both fans are tuned to come on at the same time with a temp of 2XX you will be drawing tons amps and spike a huge load on the relays. The relays might take it for some time, then when they don't want to take it anymore they will stay on and fry the wires. I have mine set up to turn on one fan at xxx and both to be on at xxx, and with the a/c on both fans on low at xx psi and high at xxx psi. You can also set a time delay for them to come on which helps reduce amp draw on start up. The motors in the fans can be going bad too, but I doubt that is the problem. Also if you test the fans with a battery, do an amp draw test at the same time to see how many amps your drawing with one fan then two fans on start up, and when they are running at full speed. This will help you see if your relays are being over powered. I believe the relays are 30amp relays he uses. I think they can take a 50amp spike but i'm not certain. Edited January 23, 2011 by sinr98 (see edit history) Quote Link to comment Share on other sites More sharing options...
ChinoHillian Posted January 24, 2011 Author Report Share Posted January 24, 2011 i believe fan 1 is set to come on at 195 and the other to come on at 205. the harness definitely melted again but the fans do work perfectly fine This is getting to the point where i'm just gonna get my money back from blackbear and then sell the fans Quote Link to comment Share on other sites More sharing options...
hawks Posted January 25, 2011 Report Share Posted January 25, 2011 (edited) i believe fan 1 is set to come on at 195 and the other to come on at 205. the harness definitely melted again but the fans do work perfectly fine This is getting to the point where i'm just gonna get my money back from blackbear and then sell the fans If you think the fans are good and your connections are good and your mind is set on a bad harness then you need to PM Mr.P (Steve) and get him to build you one. I wouldn't sell my fans because of a bad harness. If you have a bad ground this will cause the harness to melt to. Contact Mr.P and get him to build you one. Edited January 25, 2011 by Hawkman (see edit history) Quote Link to comment Share on other sites More sharing options...
misterp Posted January 25, 2011 Report Share Posted January 25, 2011 (edited) Very glad to hear that your truck has not caught on fire; and I mean that seriously, I have seen several efan harness failures cause serious damage underhood. Answering your question: Flowing electricity can be visualized like flowing water; when you see a river there is VOLUME of water (how much water is actually present) and there is PRESSURE (how fast/hard the current is). I grew up in Southern Oregon on the Rogue River; at the local city park the river was about 50-feet wide and 10-12 feet deep, and flowing so fast that you could not swim upstream at all, it was very dangerous and the Rogue drowns a couple people each year. On the contrary, when I lived in Austin we would take the kids to the city park where there's a similar-sized body of water (Barton Springs) except that at Barton Springs the current is so slow that the surface of the water is almost still, and Barton Springs has been the city's swimming hole forever... Both the Rogue and Barton Springs are similar in volume (voltage), but vastly different in current (pressure, aka amps). Voltage is volume/amount of electricity, amperage is its pressure. Voltage by itself is not the scary dangerous part of electricity; it's the amperage that kills. In real numbers, 1-amp of electricity is more than enough to kill you; there are many documented cases where people have been charred black with less than 1-amp; in other cases where people have survived electrical shock with more than 1-amp the reason is because the electricity flowed over the skin rather than through the skin - if you have more than 0.75-amps go through your tissue, it will become charcoal. I'm digressing, but point is: voltage is not what melts wires, it's the amperage. 40-amps is enough to begin melting 1/8"-thick steel. Another electrical concept = WATTAGE, which is simply voltage times amperage; if you have a hair dryer (120 volts) that pulls 10-amps then you can say that device consumes 1200 Watts (120 * 10 = 1200). So let's talk about EFans specifically - the fan motors consume a fixed amount of electricity from the truck's electrical system; this is designed by engineers, they figure out how many turns of wire are inside the motor and how thick that wire is etc etc etc and the final product will have a predictable electrical draw in watts. GM fan motors pull about 250-watts each; if the electricity feeding the fans is 14.4 volts, then the measured amperage will be 17.4-amps (250 / 14.4 = 17.4) and wiring that will handle 20-amps draw plus a 20-amp fuse will work all day long under these circumstances. However, if the engine is off and you are running the fans off the battery 11.8-volts, the fan motors will not care and will still pull 250-watts, and since there is not as much voltage available the amperage WILL GO UP to compensate, specifically the 'new' amperage will be 21.2-amps (250 / 11.8 = 21.2) and the wiring that was originally acceptible at 20-amps will begin to overheat. THE IMPORTANT LESSON HERE IS - when voltage goes down, amperage goes up!!! Related to that, if you have bad connections (power or ground) then you are introducing resistance in the circuit and the wiring cannot carry the desired voltage, and amperage WILL GO UP. When you add any electrical device to your vehicle you HAVE to size it to the expected amperage draw; this is exactly what I have done with the efan harnesses I supply with the Torrent efan kits. Several customers and myself have run the Torrent kits at 11.0 volts (that's 60-amps current draw) without issues; I knew during design that in the real world alternators fail and batteries run low, and I made sure that the electricals were designed for that situation. OK Lecture over. Simple answer is, the harness you are using is not designed to handle the load you are putting onto it; either (1) you have sub-standard connections between the harness, fans, power, and ground, (2) the harness is sub-standard to begin with (I doubt that), (3) the vehicle has an unusually low-voltage situation and the harness is not designed to work under low-voltage/increased amperage circumstances (a possiblity), or (4) one or both of your efans has a defective motor (shorted inside) and is drawing far more current than designed (possible, but I doubt it). I am not sure, but I think that you can measure the resistance in the fans and compare to known-good fans and determine if there is a short or defect. You can also use a volt-ohm-meter and determine if you have a bad ground or not. Mr. P. Edited January 25, 2011 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
DBTKDT Posted January 27, 2011 Report Share Posted January 27, 2011 I just ordered a dual pin harness from Black Bear and the service was Great and the harness looks very high quality! Thank you again Black Bear! Quote Link to comment Share on other sites More sharing options...
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