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OP can you confirm you saw two of these? See pic. I ask as the schematic does not align well with installation into that aluminum housing at the back of the engine. As in the E39 box in the schematic shows two 12V sources going in, and No ground. Essentially making them useless. In reality, they have a 2X 12V supplies and the case goes to ground completing the circuit when the relays close which actaully makes them independent and my test method is wrong as their schematic is wrong!
If you measure them again, go from pin #5 to ground on each relay.
Hindsight says 14V / 0.4 ohms = 35 Amps each with some safety margin.
Yeah, they are screwed into a metal manifold and have only one wire connected to each. I assumed the casing of the glow plug is the ground, which would be grounded from the metal manifold (there's a chassis ground somewhere around that manifold).
My measurements were taken with positive lead on the #5 and the negative grounded at the battery. As they heat up they will increase in resistance so I am assuming that's why it seems way lower than the 50A. Ill try to measure them when the car exits out of open loop and see the ohm readings. This was also taken at 0C or 40F, so when the temps here drop to around -35C or -31F (worst case scenario) that reading will be less. Also taking the measurement at the relay will add some resistance, verses disconnecting the glow plug and taking the measurement. So actually the reading right now is probably at around .8-1 Ohm.
Last edited by 011is250; 03-24-23 at 03:30 PM.
Reason: added some info
The parentheses around 'diesel' section indicate they are used for fans for the diesel applications. For me it's the labeling of E39, Combustion Heater Glow Plug...
This is all part of the of the ULE II emissions stuff. The sooner the engine is up to temp, the cleaner it runs. I would like to know if mine are working tho as the 350 seems like it takes forever to warm up. Especially if going down hill from a cold start. 10min later for the needle to move and blow warm air.
14V / 1.2 ohms ~ 12Amps which is well below the 2X 50A fuses...
I'll try to measure mine this weekend. No guarantees as its snowing...
How is your coolant level? I know if the rad is low on coolant it wont pull any from the overflow, so maybe going downhill shifts the coolant away from your heater core?
How is your coolant level? I know if the rad is low on coolant it wont pull any from the overflow, so maybe going downhill shifts the coolant away from your heater core?
It's more a product of not doing any work as it's barely off idle getting down the hill. The Tundra does the same exact thing. If starting cold and going up the hill, both reach operating temp in 1/2 the time.
So the 1.2 ohms was for each side from pin #5 to ground, not from pin #5 to #5?
Correct - resistance does change with temperature, we just don't know what the curve is. I wonder if I can see this trigger on with OBD Fusion?
From the schematic we know the name. There is that.
The purpose for the air conditioning turning on is so that it chills the air to condense the moisture molecules within it...... Once the moisture particles are condensed, the heating system heats that cold air to evaporate the moisture and expel it from the circulating air.
Not quite. The water that condenses on the cold evaporator core runs out a drain hose under the car. That cold dry air is then reheated in the heater core and warm dry air flows from the defroster outlet.
So if you press defrost, what does it do now? It still blows on the glass at high just using the current temp settings?
I'd like to disable the full speed fan as it's so loud. Was that an option?
Yeah both buttons (physical defrost button, and touchscreen defrost/feet) just work as is, minus the a/c compressor turning on. Are you talking about that initial fan speed that goes to max when you press the physical defrost button? There is an option called "auto blow up function". However I havent messed with it, currently I can adjust the fan speed on either defrost options, with the initial fan speed going max when pressed.
03-24-23 | 03:16 PM
