Genuine Bosch (left) & Generic Blazer brand (right)
Notice the quality of the contacts!

Well you all know by now how I build control circuits for everything in my truck, well awhile back I had installed a relay for my AC compressor clutch and I had gotten a generic ISO relay from Auto Zone to fix this in the field.
Anyhow after I built a permanent circuit for this I used the same relay for now so I did not have to go into my relay stock. Last week the AC started to get kind of sketchy so I checked it out and sure enough the relay would pull in but not engage the clutch. I simply replaced it and installed a genuine Bosch relay in its place and then back on the road nice and cold. So I decided to check and see what was the problem so I opened up the case and found out just how cheap these things are assembled. I only used it because it was already in the circuit.
I have 4 relays on my headlights, AC, ICC flash, starter interlock, brake and turn signals for my 7 way, backup lights and a lot of other devices.
I guess what I want to share with all of you is be sure to use only genuine Bosch relays on anything that’s of a critical nature such as headlights. You would not want your headlights to fail when you need them the most. Spend a few extra dollars and get the good ones.
It is also a good idea to install a small diode across the coil to clamp the spike it produces when the field collapses. You can buy these relays with an internal diode or resistor from any truck parts.

Thanks for listening. Jim

 

if I started working that stuff on my truck you would see nothing but a big fire I'm just happy I can wire the 7-way plug out back
DM01