Am I safe to run both fans on one 30/40a relay? Or will the fan startup draw be too much for the one relay?

 

I would say no since they got 3 relays from factory for high and low speed use but one per each is how i do it

 

I don’t think these fans have dual speeds?

 

It’s easy enough to run a second relay, just thought it would be a lot cleaner with one. Do you run both fans out once? Or are they set to come on at separate times

 

Mine are separate times

 

They do with the factory 3 relay setup. For low speed the fans are wired in series and run on 6 volts. When they go to high speed they are run on separate 12 volt supplies and voltage increases to 12 volts per motor which makes the setup draw 4x the amperage.

I had 2010 Tahoe fans on my Express van. They use higher wattage motors and bigger fan blades than the 4th gen fans. The Tahoe fans drew 10 amps on low and 40 amps on high. Just ballpark, the 4th gens probably draw 7.5 amps on low and 30 amps on high.

 

Makes sense. Thanks

 

Thanks for that. I remember it was like that but didnt know exactly. I wired an s10 ls1 swap like factory a few years ago

 

I would definitely use a separate relay for each fan. You can get higher amperage relays (~70 amps). However, having separate relays is a safety net in case one goes out you still have the other relay/fan working.