amsisubaru

My fan went on and off, after a bump or pounding the dashboard with my fist. I read this newsgroup-- that the bad unit could be relays, switches, and fan resistors. I finally removed the dashboard, slid out the AC / Heater control panel, unplugged the connector in the rear and took the front of the control panel case off. Two more screws and I lifted off the rear circuit board and examined the solder points for the plug connector. Several of the solder connection had very fine cracks and when I moved the plug part I could see the cracks (and the soldered pin) move, but, this is very small movement and small cracks. Under a 4X lens the cracks on three pins were easier to see. So, I simply reheated the solder joints on all the pins and added some fresh solder to make a more secure phsical connection. Instant and complete relief! The reason the solder joints cracked in the first place is that the wire cable and plug that connects to the rear of the control panel has significant inertia. After 15 years the bumping and jarring wiggled that plug enough to crack the joints, even with strain-relief strapping. After the cracks developed, oxide probably built up enough to hold the connection open until another bump (or my fist) knocked the connection together again. I ran through a lot of tricky hypotheses trying to find a way around taking that dashboard off, like the relays, a vaccuum leak, the diaphragm, and the fan motor. Also, since the fan often started when I first started the car I though it might be some sort of element heating. Good luck.

My fan went on and off, after a bump or pounding the dashboard with my fist. I read this newsgroup-- that the bad unit could be relays, switches, and fan resistors. I finally removed the dashboard, slid out the AC / Heater control panel, unplugged the connector in the rear and took the front of the control panel case off. Two more screws and I lifted off the rear circuit board and examined the solder points for the plug connector. Several of the solder connection had very fine cracks and when I moved the plug part I could see the cracks (and the soldered pin) move, but, this is very small movement and small cracks. Under a 4X lens the cracks on three pins were easier to see. So, I simply reheated the solder joints on all the pins and added some fresh solder to make a more secure phsical connection. Instant and complete relief! The reason the solder joints cracked in the first place is that the wire cable and plug that connects to the rear of the control panel has significant inertia. After 15 years the bumping and jarring wiggled that plug enough to crack the joints, even with strain-relief strapping. After the cracks developed, oxide probably built up enough to hold the connection open until another bump (or my fist) knocked the connection together again. I ran through a lot of tricky hypotheses trying to find a way around taking that dashboard off, like the relays, a vaccuum leak, the diaphragm, and the fan motor. Also, since the fan often started when I first started the car I though it might be some sort of element heating. Good luck.

My fan went on and off, after a bump or pounding the dashboard with my fist. I read this newsgroup-- that the bad unit could be relays, switches, and fan resistors. I finally removed the dashboard, slid out the AC / Heater control panel, unplugged the connector in the rear and took the front of the control panel case off. Two more screws and I lifted off the rear circuit board and examined the solder points for the plug connector. Several of the solder connection had very fine cracks and when I moved the plug part I could see the cracks (and the soldered pin) move, but, this is very small movement and small cracks. Under a 4X lens the cracks on three pins were easier to see. So, I simply reheated the solder joints on all the pins and added some fresh solder to make a more secure phsical connection. Instant and complete relief! The reason the solder joints cracked in the first place is that the wire cable and plug that connects to the rear of the control panel has significant inertia. After 15 years the bumping and jarring wiggled that plug enough to crack the joints, even with strain-relief strapping. After the cracks developed, oxide probably built up enough to hold the connection open until another bump (or my fist) knocked the connection together again. I ran through a lot of tricky hypotheses trying to find a way around taking that dashboard off, like the relays, a vaccuum leak, the diaphragm, and the fan motor. Also, since the fan often started when I first started the car I though it might be some sort of element heating. Good luck.

I had a similiar problem with my 1990. Here's the post. My fan went on and off, after a bump or pounding the dashboard with my fist. I read this newsgroup-- that the bad unit could be relays, switches, and fan resistors. I finally removed the dashboard, slid out the AC / Heater control panel, unplugged the connector in the rear and took the front of the control panel case off. Two more screws and I lifted off the rear circuit board and examined the solder points for the plug connector. Several of the solder connection had very fine cracks and when I moved the plug part I could see the cracks (and the soldered pin) move, but, this is very small movement and small cracks. Under a 4X lens the cracks on three pins were easier to see. So, I simply reheated the solder joints on all the pins and added some fresh solder to make a more secure phsical connection. Instant and complete relief! The reason the solder joints cracked in the first place is that the wire cable and plug that connects to the rear of the control panel has significant inertia. After 15 years the bumping and jarring wiggled that plug enough to crack the joints, even with strain-relief strapping. After the cracks developed, oxide probably built up enough to hold the connection open until another bump (or my fist) knocked the connection together again. I ran through a lot of tricky hypotheses trying to find a way around taking that dashboard off, like the relays, a vaccuum leak, the diaphragm, and the fan motor. Also, since the fan often started when I first started the car I though it might be some sort of element heating. Good luck.

My fan went on and off, after a bump or pounding the dashboard with my fist. I read this newsgroup-- that the bad unit could be relays, switches, and fan resistors. I finally removed the dashboard, slid out the AC / Heater control panel, unplugged the connector in the rear and took the front of the control panel case off. Two more screws and I lifted off the rear circuit board and examined the solder points for the plug connector. Several of the solder connection had very fine cracks and when I moved the plug part I could see the cracks (and the soldered pin) move, but, this is very small movement and small cracks. Under a 4X lens the cracks on three pins were easier to see. So, I simply reheated the solder joints on all the pins and added some fresh solder to make a more secure phsical connection. Instant and complete relief! The reason the solder joints cracked in the first place is that the wire cable and plug that connects to the rear of the control panel has significant inertia. After 15 years the bumping and jarring wiggled that plug enough to crack the joints, even with strain-relief strapping. After the cracks developed, oxide probably built up enough to hold the connection open until another bump (or my fist) knocked the connection together again. I ran through a lot of tricky hypotheses trying to find a way around taking that dashboard off, like the relays, a vaccuum leak, the diaphragm, and the fan motor. Also, since the fan often started when I first started the car I though it might be some sort of element heating. Good luck.