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View Full Version : Large relay for Mark VIII Fan, source?



Blown353
12-30-2004, 10:03 PM
I'm helping a friend with a Mark VIII swap on his 68 Camaro. My old web source for large Bosch relays isn't good anymore.

Does anyone have a source for a large (75+ amp) relay for use with the Mark VIII fan? I'd prefer a major brand (Bosch or Hella), I just can't seem to find any suppliers online.

Thanks,
Troy

camcojb
12-30-2004, 10:17 PM
75 amp Bosch relay (http://order.waytekwire.com/IMAGES/M37/catalog/217_053)

Jody

my72vette454
12-31-2004, 09:43 AM
The one I used on my fan is like a ford starter relay. I think it is made by standard and you can find them at the local parts store. They have 2 types, internal ground and external ground. I used the external ground and am grounding it with a one wire thermostat switch in the head. Seems to work good so far.

Mike

gmachinz
12-31-2004, 02:39 PM
I use Hella relays rated @ 70-amp with diode. Part number is 87103. I can order them from my supplier for around $35. -Jabin

MarkM66
01-05-2005, 07:04 AM
How many amps does this fan pull?

Can you just use two 30 amp relays?

gmachinz
01-09-2005, 05:53 AM
I was told by the dealership that the fans draw a continuous 33 amps-but without a controller, voltage spikes can reach as high as 100 amps @ initial turn/on I am told. I just like to keep things simple with one big-@$$ relay-less wiring. :icon996: I like to cover my bases at every angle.

derekf
01-09-2005, 05:19 PM
Keep in mind that if both relays don't trigger at the exact same time on turn-on (I mean down to the millisecond) then for a tiny split second only one thirty amp relay will be taking the whole load... which will cause arcing and premature wear of the contacts.

The odds of getting both relays to make contact simultaneously are really, really bad.

I'll be using a single large relay.