Bob, perhaps this lowly neophyte to this board can provide some guiding light…
Assuming that your coach has not been victimized by “blow torch and hammer mechanics” in its past, I’d like to explain and suggest the following:
Abstract:
In an Eagle, model 10, the HVAC (for Heating, Ventilation and Air Conditioning) assembly for the driver is physically located below the driver’s seat in the spare tire compartment. The driver’s HVAC features a squirrel cage bower that is directly driven by the shaft of a sizable DC motor.
Because of the blower motor’s high current demand on the vehicle’s 12VDC electrical system, Eagle Manufacturing designed a control system that prevents catastrophic vehicle battery discharge. That is, the HVAC can only operate during travel or when the coach is parked with the main engine running.
Domain:
The electrical interfaces for the blower motor control are routed through three domains (for lack of other words): (1) Dash panel (DP), (2) Power Distribution Panel (PDP) -- front, driver side -- and (3) C&D panel above the engine compartment at the back of your coach.
Controls/Indicators:
At the driver’s dash there are four switches and an indicator light located on the outer left panel. The switches are usually labeled (1) MAIN A/C, (2) MAIN BLOWER, (3) DRIVER BLOWER, (4) DRIVER AC/HEAT and the indicator light COMP LOAD.
The control of interest here is the driver’s blower high/low speed function. The “BLOWER MOTOR Hi/LOW” switch has three connections. Wire #52 is feeds (connected to) +12V from the C&D panel above the engine compartment at the back of your coach, wire #96 is the Power Contactor Enable output and wire #165 is the Blower Motor Low Speed Enable control.
Functionality:
+12VDC power to the driver’s A/C - Heater blower motor is enabled by the “Driver’s Blower Solenoid” and fed through a heavy gauge cable #94 from the back of the bus via the front power distribution panel directly to the blower motor terminal L2. The negative terminal L1 is connecter to chassis ground. You will find that the driver’s blower solenoid is the third one from the right on the C&D panel at the rear of the bus.
The driver’s blower motor is enabled (turned on) and operated at two different speeds via a voltage (12VDC) applied to terminal (F1). This connection is provided via wire #166. However, the device that actually enables the blower is relay K5 (Voltage Regulator) located at the C&D panel. The output voltage from the Alternator/Regulator assembly is fed via wire #97 to contact 86 of the relay K5 (you can test the voltage at terminal T-97 at the C&D panel -- the relay is the second one from the right).
When K5 is enabled and contacts 30 – 87 close, 12VDC from the vehicle batteries is applied via the closed contacts of relays K7 (Main Blower Motors) -- which is also enabled by the alternator/regulator voltage -- and fed to relay K9 (Main A/C). There is a 20A fuse in line between K7 and K9. You will find that fuse between contacts 90 and 150 on the fuse board located on the right side of the C&D panel. You might as well check for continuity at this point.
K9 (Main A/C) is enabled by the voltage applied through the contact 30-87 closure of relays K5 and K7. This applies 12VDC from the vehicle batteries via the closed contacts 30-87 of K9 though a 20A fuse via terminal T-52 (on the C&D Panel). You will find the 20A fuse between contacts 88 and 52 on the fuse board located on the right side of the C&D panel as well. You can check that control voltage on terminal T-52.
From T-52, wire #52 is routed from the C&D panel at the rear of the coach all the way forward to the front PDP via its terminal T-52 the control switches “A/C-HEAT” and “BLOWER MOTOR Hi/LOW” at the driver’s dash. Either switch cannot operate if this voltage is not applied. You can check the control voltage on terminal T-52 on both the C&D panel and the PDP up front.
The relay that controls driver’s blower speed is K2, the Driver’s Blower HI/LOW relay. You’ll find it at the front PDP. It is energized by the above mentioned “BLOWER MOTOR Hi/LOW” switch. Continuity between contacts 30 and 87a runs the blower at full speed. Continuity between contacts 30 and 87 connects a resistor in series and, thus, runs the blower at reduced speed.
So, here you have it. This is the way this arcane circuitry came to fruition at the wonderful world of Eagle manufacturing
Following are the steps I would pursue:
— Make sure the terminal L2 of the driver’s blower motor is properly grounded and 12VDC is applied to terminal L1 when the main engine is running.
— If not, then the driver’s blower motor is not enabled (turned on). Check this voltage at terminal T-166 at the front PDP.
— Make sure that the voltage at terminal T-97 does not fluctuate during idle. If it does, then you almost certainly have a regulator problem.
— Focus on K5 (Voltage Regulator relay). Make sure that the connections are clean and the relay energizes when 12 VDC is applied to contact 85 and 86 is properly grounded.
— Test the input voltage to relay K5 at terminal T-97 at the C&D panel -- the relay is the second one from the right).
— The Heater Boost Pumps are controlled by Relay K8. Same methodology applies here.
— Make sure the Blower HI/LOW switch is working properly. Check the control voltage for K2 (Driver’s motor) on terminal T-165.
— Check the input voltage from K2 to the blower motor on terminal T-166. You will see a voltage change onT-166 when you flip the BLOWER MOTOR HI/LOW switch.
— Make sure that a steady 12VDC is present on terminal T-96 when you flip the BLOWER MOTOR Hi/LOW switch.
— Make sure the Power Solenoid does not bounce when voltage is applied to it via terminal T-96.
Good luck -- Viel Glück -- Buena suerte -- Bonne chance,
Chris