A/C Blower help!

[Hercpilot]

Okay...Searched for previous write-ups and found nothing!

Here we go!

I am putting a Four Seasons A/C system in a non-A/C truck. I am using a donor truck for all the necessary essentials. I am up to the point of wiring everything.

My issue is this....fan runs on low & med with the blower relay not grounded (as it should) but when I ground the relay, my resistor wires get red hot on both low and med settings and the blower motor stops running. So with the blower relay grounded, I take the fan switch to high and it runs perfect and the resistor wires cool down!

So as it stands, I can choose either to have low/med only with an ungrounded blower relay or have high only with a grounded relay and avoid not putting the fan switch in either low or med to avoid overheating the resistor!

Any thoughts?

BTW...wired per service manual schematic, wires have been ohmed, grounds checked, new fan switch and new blower relay.

Justin

[Katrina/10]

The resistors are supposed to get hot on low and medium speeds. I had the same problem, changed the blower motor and it worked fine.

[Hercpilot]

Changed the blower motor. Problem persists!

Justin
Posted via Mobile Device
Posted via Mobile Device

[Hercpilot]

Finally figured it out! This has been bugging me for way too long.

So....I had a brand new relay, switch and a fully functioning motor all with properly conducting wiring. The red hot resistor was really a huge flag. Something somewhere was drawing way to much current. I saw "USA" stamped on the blower relay initially but it never entered my mind again until tonight. I thought, why not open it up. So, I did. As it turns out, one leg of the relay was grounding on the metal case surrounding it. I never thought to check the continuity on each leg of the relay.

I did a little bending/massaging on each of the two main legs of the relay so as to move them as far away from the case as possible and still retain the functionality of a relay. In addition to that, I also took a punch to the case where I suspected the internal components to be grounding and dented that area away from the internals.

All is well now with the blower function!

Justin