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Fan clutch Relays?
I put this question on the Vanner post, Jim made a comment about Relays W/Resistor and Relays W/O Resistor. Got me thinking about this a while back I replaced my two 24v relays R78-R79 that control the fan clutch and Prevost sold me two 24v relays W/resistor and then I looked at old ones and I don’t think it has a resistor. Looked on Prevost website and found Prevost part # 561707 which means nothing to me. What affect on fan clutch would a resistor make?? R78 & R79 it removes a ground signal to make fan work, Any thoughts?? Top pic is OEM that came out of R78 or R79 and bottom Pic is from Prevost Also is the Resistor on the coil side or the contact side?? I think the resistor is on the coil side after checking it out with meter.?? I took two more pictures 1st pic of meter 360 with out resistor 2nd pic 291.3 with resistor.
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Art. This is how Chris described it to me. The relay in side drivers window compartment that we had issue, comes from a 12 volt ACs current off DN-50, unrectified. Meaning its “alternating current, not 12 v or 24 v. The resistor equipped relay would not allow the alternated AC 12 ac to pass. On the coil side we think the resistor helps to keep relay cooler to last longer We think the only use for this 12 v AC signal from alternator to dash battery light is to let you know if the 50 DN has taken a dump. And consequently, cuts power to appliances like OTR, blower, fan clutch, front coolant heater pump. Earlier coaches may get their 12 v AC signal from DN50 directly to the R78 and R 79 which in those cases, maybe 12 volt AC. But without a wiring diagram specific to that earlier coach, dont know. We searched ours out on the Featherlite Prevost diagram particular to our bus and Chris found it, being unrectified type under drivers seat
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