i can NOT find my damn multi meter..I'm so pissed. i guess I'm going to go buy a new one..i just got done pulling the dash on my girlfriends 92 mx6 to change the clogged heater core. that was a 6 hour job..sucked!! then i pulled my rx7 in and pulled the seats and some other stuff off the interior. tomorrow i hope to get the dash pulled then ill be able to get at all this stuff easier. do you know what that means when i jumperd the yellow/black to the green/black and i heard the relays click over but the fan didn't kick on? what does this mean?

 

IF both relays clicked then it means the resistor is burnt in two. The resistor is on the bottom of the housing. It's held with two phillips screws, then pulls straight out. It looks like a coil spring with both ends soldered to the plate.

Relays pulling in mean the Logicon is good. It takes a gnd from the logicon to pull the relays in once you've established power on the positive side of the relay(s).

See attached jpg of the resistor. I soldered that one back on the plate and now the fan works and all that good stuff.

The relays pullng in when you did the jumper job means to me, that the ground for the Ign relay is not there. That ground comes from the small wire on the starter solenoid. I suspect someone has rearranged the wiring on the starter where that small wire is not connected to the heater eight socket connector anymore.

The blue/white and red/yellow wires in the jpg attach to the spring/resistor. If the spring isn't in one piece it creates an open circuit for the fan.

The second jpg is from a 87FSM wiring section. It shows the resistor to the right of the page. The 88FSM does not show this resistor nor does the series five FSM. So I assume they did away with this item on those cars. It seems to be a weak point in the 86-87 heaters.

EDIT: Still, the low speed shouldn't work if that resistor is open, but the Ex-Hi should work. With the slider all the way to the right that is.

 

im going to radio shack now to buy a new volt meter and new soldering gun tips... so once i fix that resistor i will still have other issues?

 

I'd take the ten minutes to unscrew the resistor outfit and see if it's broken or not first. It's on the bottom of the case. Two screws and it pulls straight out.

If you already looked, then fixing it SHOULD fix your fan/heater problems.

I'm watching No Country for Old Men right now for the upteenth time.

 

oh that movie is awesome! i watched it like 3 times myself haha

i just went out and bought one because i use the multi meter alot so its something i needed anyway. so ill check that out tomorrow. but didn't you say even if the resistor is bad, the low setting should still work? does this mean i may have other issues even if i repair the broken resistor?

 

It's up in the air. I just went out and disconnected the resistor and turned on the fan. It worked on low but not high. Reconnected the resistor and both worked.

That resistor has two wires going to it. A red/yellow and blue/white. Without those in the circuit for some reason the high does not work.

One thing I'd do is this. Go out to the car. Jumper that black/yellow to the green/black like you did earlier. But this time feel each relay as you do that and determine if both relays are clicking/pulling in. Just curious. You have to make the slider on the logicon go full right for the Ex Hit to pull in.

Tomorrow I might go out and disconnect that resistor at its plug. Then jumper the plug to simulate the wire resistor being in place, and see what happens when I turn the fan on. That wire resistor is something(another thing) I don't understand. Like why it exists in the first place.

 

yes when i did it the first time i felt the relays and both of them are clicking/pulling over. i will have the dash out by around 12 or 1 eastern time tomorrow...

 

OK i got the dash out, and wow what a mess!! this thing has aftermarket wiring EVERYWHERE!!! its all for the gauges, turbo timer and stereo. there was 6 small gauges and a monster tach. and then i wired in a microtech lt10 and a water injection controller. i cut out all of the gauge wiring and disconnected the turbo timer and plugged the ignition back in to where it was suppose to be. i didn't realize the timers harness just bridges the 2 factory plugs. so you can just unplug the turbo timer harness from both ends and plug the factory plugs together and its like it was never there. I'm going to need some help from you to get this thing wired back to how it should be. i will be installing only 3 of the gauges back in though. water temp, wideband and boost. do you know of any pictures of the wiring on the body itself behind the dash? i removed that resistor spring thingy and it wasn't broken but it had some kind of burnt charcoal looking **** on it..? it was a hard gray crust stuff that just crumbled off when i touched it..im probly going to snap a bunch of pics of the dash area and start a differnt thread about getting the other wiring back to normal and instaling the gauges the right way this time.

 

That resistror (coil spring outfit) has a plug on it. Remove the plug from it. The put the meter on ohms and put one meter probe to each of the prongs on the resistor. It should read about 1ohm or so.

Or try this. Remove the plug from the resistor. Then jumper both sockets on the PLUG and turn the key ON and slider to the far right. It should blow.

Or here is something do. Go to the transistor and pull it's plug off. It has three wires on it. A red/yellow and blue/white and then a smaller wire that is blue/orange.

Put your meter on volts dc and the negative lead to a known ground. The positive meter lead in the blue/orange socket of the plug. Then key to ON. You should see voltage on the meter. Now slide the slider back and forth. It should go from something like 5vdc up to 9 or 10 volts dc. If it does , then the logicon is good as far as the slider goes. IF you get the blower to blowing, and it only has one speed when you move the slider to the right, then the transistor is kaput in the housing. But the blower should blow higer as you move the slider far right. That part is not controlled by the transistor.

You'd do all the with everything connected up. As far as the part were I advised jumpering the green/black to the black/yellow, well you can either do that or pull the plug off the IGN Relay and jumper the two upper sockets on that plug and that will do the same thing. Like getting a piece of wire and crimping two male connectors on that wire and then installing that wire on the upper two sockets of that Ign Relay plug.

I suspect your blower housing is shot. You might go to the wrecking yard and get another.

But that won't solve the lack of a gnd for the Ign relay. I've no idea why your ground isn't there, so even with a new/used housing, you'd still have to jumper the two sockets on the Ign relay.

I might post a jpg of the jumper I mentioned above, tomorrow.

I'd certainly do the bit above where you look at the voltage of the blue/orange wire on the transistor plug. That more or less proves if the logicon is outputing voltage to the transistor ....or not.

Housings sell for ??? ten to fifteen without the blower and not much more with the blower.

 

ok but now my dash and harness is ripped out lol how do i test these things? i guess can i just remove the harness from the dash and hook it to the car. i have another heater housing at my work on a parts car. when you say the heater housing is bad what do you mean? and are you saying the plug with the orange/blue wire i need to test for voltage is the one thats about 5 inches from the spring/resistor right? the one that connects to the resistor?

 

can you show me a picture of what the transistor looks like?

 

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1. If the plugs are off both the resistor and the transistor assy's, the fan will only work when the slider is put to the far right (hi speed).

2. If the plug is off the transistor and On the resistor, the fan will run by just putting the slider to the right, but will only run at one speed.......until the slider is put to the far right and then it blows hard (hi speed).

3. If the fan speed is only slow when the slider is put to the right and never speeds up until you turn on the Hi speed, then the transistor is bad. Or if it blows slow speed and NEVER gets any higher, then the transistor and resistor are bad.

4. If the fan never runs but you KNOW that the Heater relay is pulling in and KNOW the Ex Hi is pulling in when the slider is far right, then either the HEATER breaker is open OR the Heater relay is bad internally.....even though you hear/feel it pull in. So if you feel it pull in just put the relay to the side and jumper the R/Y and L wires and turn the key ON and slider to the right. The L wire comes right off the HEATER BREAKER and the R/Y feeds the Ex Hi relay, transistor and the resistor. The blower should run if this is done and the Lg/B is feeding the relays and Logicon.

 

ok heres the deal, i got my heater box pulled out and i also pulled the box out of my parts car and i was shocked.. the car we have been talking about is an 87 turbo II and the box looks just like the one in your pics. now the one i pulled out of my parts car is an 88 convertible, look at how differnt the wiring is, there are no diodes no ressistors (spring) ant the flap that you see inside the box is solid on the 88 vert box but the TII box has a small flap in the middle of the big one.. can use this box? check out the pics they can explain this better.. in the pictures it looks like the white one is missing wires but its not, everything is there and it has all the same plugs that go to the body harness of the car



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oh yeah and this thing dosent even have a ignition relay??? so how does it cut out when you go from the on position to start? if i can use this it seems like it would rule out almost all the things we have been testing? have you ever seen a box like this? im goin to check the fsm now and see if i can find one that looks like this.

 

I've made mention in my post how the wiring diagrams for the 86-87 appear different than the wiring shown in the 88 online wiring.

The 88 wiring diagram does show a resitor/spring. The diodes are missing on the 88 because the diodes were used in conjunciton with the Ign Relay.

Seems that might be a series five blower unit????????

The eight socket plugs for a 88 are ALMOST the same as a 86-87 except for the BG wire missing in the bottom left of the 88 plug. That wire on a 87 is used to put a gnd on the ign relay. The 88 does not need that wire. The rest of the wires seem the same.

The item that is missing, is the single plug/wire that fed power from the 87blower unit to the Logicon. I don't see how the logicon could work right without that wire.

Plugging the eight socket in seemingly can't hurt a thing. I've some doubts if it'll work though.

If it does not work, find a source of batt power and feed it to that light green/black wire/plug and then see if it works or not.

Series five heater cases/motors dont' use the resistor/spring thing. See S5 diagrams.

I'd check the part number on the LOGICON in your car and look in the parts fische to see if it's for a series??????????????? four or not.

 

The more I looked at the more I'm sure if the plugs were connected up and the light green/black plug/wire were fed power, then that series???? blower would work.

 

i am almost 100% sure this is the original heater box and the car is a 88 S4 for sure.. all the plugs are the same its just like they eliminated alot of stuff out of the harness.. so do you think i should go ahead and install it without giving the green wire power and see if it works, then if it doesn't just connect it to one of the other wires that has ignition (on) power. say maybe the thick blue one? cant remember if that one has ignition or constant power.. and what do you think about the differences in that flap? why are they different and do you think the solid one on the white box is ok to use?

 

quote"I'd check the part number on the LOGICON in your car and look in the parts fische to see if it's for a series??????????????? four or not. "

where can i find the parts fische?

 

today i installed the white box and it didnt work so i put the black box harness on the white box and it still didnt work so my logicon must be bad...

 

Parts fische url is in the FAQ thread.

Did you run batt voltage to the light green/black? I mean, the white box does not have that single connetor. The logicon has to get power, and the light green/black is the power wire.

And the NON WHITE heater case/motor are in your picture are 86-87 ones. The white one Is Not.

 

damn no i forgot to run power to that wire..i was kind of in a hurry.. im going to try that tomorrow, if that doesn't work im buying a new logicon and heater box. and if that doesn't work im just hooking a ******* toggle switch to the blower and running it manually. this is so frustrating!!!

 

still got a working logicon and heater core blower unit for sale pm for price

 

ok hailers this is what we got here....i installed the white box and jumped that green/black wire to a 12v source and everything works perfect!! then i hooked the old one up and jumped the green/black wire to 12v and it didn't work... so what do you think i should do? can i just hook that wire up to an ignition on 12v source and be done with it or wont that be good?

 

*EDIT* the blower only works on the max setting like this so im not sure why that is...also when i put the meter on the green/black on the heater housing side i get nothing