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Part missing? (1990 Ford E350 Econline rear heat/ac)
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completelyhis
User
Mar 23, 2007, 9:34 PM
Post #1 of 6
(5225 views)
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Part missing? (1990 Ford E350 Econline rear heat/ac)
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Our church is going to Mexico on a mission trip in one week, and I still have two major issues to work out on the van! Here's the story with the rear ac/heat: It looks like the factory installed system (I'm told there were some aftermarket jobbers done, but this doesn't look like one). I got the AC system tested, repaired, and charged w/ 4.5 lbs of R12, and the front works GREAT! The rear, however, does not put out cold air at all. The mechanic told me he thought it was the expansion valve going to the rear evaporator coil (wanted nearly $300 to fix it, and we're already over budget on this trip!). I pulled the driverside interior panel off, felt started the van, turned on max ac and felt the evaporator coil...it got quite cold within seconds. Also noteworthy is that the heater core got really hot as well. Here's what I know about the system:
1. there are no independant rear controls for temp, only fan spead (located on dash) and switch lever for vent/floor in the rear
2. there is no visible mechanism for keeping the heater core from getting hot while running ac, there is no mechanism for enabling the fan to pull air through the evaperator coil w/out pulling it through the heater core as well.
3. there are some wire coils that get hot located after the fan, near the vent duct...they get hot no matter what, if the fan is blowing, no matter if heat/cold/ac...whatever.
4. I remember noticing that there would always be hot air coming from the rear vents...just "drifting" out slowly if the rear fan was low/off, but if I set the controls on "vent" and turn on the rear fan...HOT AIR!!
seems to me that there should be some method of keeping the hot water out of the heater core when you don't want heat, or diverting the area to keep the air from flowing through the heater, if you want vent/ac...
Either way, I think the mechanic is wrong about the expansion valve, because the evaperator core gets cold pretty quick. so, I think either the rear system exists only to defrost and heat (seems like a lot of extra hardware for that!) or there is some component missing...or malfunctioning.
any ideas?
ps..2nd issue is turn signal, I'll find the appropriate place to post that one!
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steve01832
Veteran
Mar 24, 2007, 4:06 AM
Post #2 of 6
(5223 views)
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Re: Part missing? (1990 Ford E350 Econline rear heat/ac)
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Check to make sure the heater control valve is working properly to close coolant flow to rear heater hoses when AC is selected. This is located in the engine compartment or on top of the engine. If the evap is getting cold then the system is working. The heater hoses should not be hot. If there is no control valve for this vehicle, then there has to be a door in the rear module to close off the heater core so that the fan will blow across the evap only. Let us know how you make out.
Steve
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completelyhis
User
Mar 24, 2007, 8:55 AM
Post #3 of 6
(5222 views)
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Re: Part missing? (1990 Ford E350 Econline rear heat/ac)
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I looked all over in my Chitlons manual, plus with my own two eye, digging around the van. The manual says nothing of a valve, which I thought was weird, because I was thinking the same as you! Any idea if it is vaccum or cable controlled? It has to be some how connected to the temperature selector on the dash, which seems to only control the diverter in the front. Seeing no cabling for a rear diverter, there must be a valve to shut off coolant, as you have mentioned. I will keep looking...any clues will be very helpful!
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completelyhis
User
Mar 24, 2007, 11:02 AM
Post #4 of 6
(5221 views)
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Re: Part missing? (1990 Ford E350 Econline rear heat/ac)
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spent another hour looking today...no valve to be found. I traced all the heater hose from the block to the T, where it splits to the front and rear heater cores, traced to both of those...no valve. leads me to several possibilities:
1. I'm not good at looking for things
2. I'm wrong, the mechanic is right
3. there are some guts missing from behind the driverside panel where the rear AC is, which would serve as a diverter
4. the rear is not supposed to produce cold air
any thoughts?
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Mar 24, 2007, 11:35 AM
Post #5 of 6
(5220 views)
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Re: Part missing? (1990 Ford E350 Econline rear heat/ac)
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Possibly a diverter or blend door that doesn't move properly and may be controlled by vacuum or by electric - not sure. The rear system was almost certainly made for A/C especially by you saying the evap gets cold there, T
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completelyhis
User
Apr 7, 2007, 10:33 PM
Post #6 of 6
(5201 views)
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Re: Part missing? (1990 Ford E350 Econline rear heat/ac)
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It was the water shut off valve. Come to find out, there is one, located on the drivers side of the engine compartment, accessible from the cabin, with the dog house removed. Couldn't see it at first, but a friend helped me snoop, and spied it out for me. the vaccuum line was not getting suction (the shut off valve is vaccuum activated)...tried putting the temp selector all hot, all cold, no vac (engine running) also tried moving vent/ac/heat/defrost, still nothing. followed the vac line to the front blend door, found it was disconnected it. the line was getting vac, but the rear heater core was still getting hot!!
replaced the shut off valve. With the valve shut, I was able to pull air through it with my mouth...don't know if that is normal or not, but after putting the new one in, the rear heater core only gets hot when it is supposed to!!!!
Thanks for all the help!
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