Did some more troubleshooting. First off, the voltages to both the low speed and high speed relays are there. That is both the triggering voltage, and the main voltage. The high speed relay, in the "un-energized" state passes the voltage to the low speed relay. I pulled out the low speed relay, and put a jumper between pins 6 & 2 (see diagram), and the low speed fan came on. That means the entire fan assembly is good. This was done while I also had a jumper in the temp sensor low speed pins 2 & GND.
Hopefully, that would point to the low speed relay being the problem. When I swapped the AC fan relay, and the low speed relay, the fan did not come on. So either both the fan relay is bad & the low speed relay, or it is not the relay.
I did turn on the A/C, and the high speed fan came on. That would imply the A/C fan relay is good.
Looking at the diagram, it appears the DME sits between the path of the double temperature switch and the actuating function of the low speed relay. This is not the case for the high speed relay, and explains why when I jumper ed pins 1 & GND of the temp switch, the high speed fan came on.
So I can force a connection across pins 2 & 6 of the low speed relay, but I can't get the GND from the DME to actuate the low speed relay properly.
Again, that assumes the relay isn't bad. I only hope the relay IS bad, that would be an easy fix. If not, I must trace the path from pin 2 of the temp switch, through pin 68 of the DME, then out pin 57, and finally to pin 5 of the low speed relay.
Can I get the low speed relay at a parts store, or only at the dealership?
Any thoughts?
Quote:
Originally Posted by JNCoulombe  If you tried swaping the low speed relay and the low speed still didn't work when you used a paper clip to jumper around the fan switch (as described by campaiar) the fan switch (temperature sensor) is probably not the problem. The next obvious thing to check is the continuity of the fan low speed resister mounted on the back of the fan. |