Blower Motor Relay Order (Pwr. Dist. Box)

[91explorer1009]

I have searched a lot for this, and I am pretty sure my problem is a bad blower motor relay. The only problem I am having is figuring out which relay out of the three it is? I have an intermittently working fan, on and off sometimes...

From searching I believe that the green, closest to the firewall is the fuel pump relay. Which of the other two is the blower motor relay. Some searching has left me confused, some people have said one is the eec and the other is the a/c wot?? No blower motor it sounds like. Others while searching have said it is under there?

I have posted a pic of what my truck looks like, since some of the later models differ, with nice relays right on top, with a LABEL, on the underside of the cover. HMM, anyway, which is my blower relay? Also what is the correct relay for what? What are all three under there? Thanks so much, I have been at this for days.

 

[arco777]

Why not try by process of elimination? Unplug one and see what happens...

Fuel pump relay unplugged, you wouldn't hear the pump prime when you turn key to RUN. EEC relay unplugged, the Check Engine light wouldn't light up when you turn key to RUN.

 

[91explorer1009]

I could try that, thats a good idea. Somebody here has to know the order though, especially if one even definately is for the blower or something else??

 

[91explorer1009]

Bump...anyone have a solid answer as to the order and what they are? Someone has had to replace these before...

 

[arco777]

Bump...anyone have a solid answer as to the order and what they are? Someone has had to replace these before...

No offense, but, finding it by process of elimination would take maybe two minutes, and you've waited six days total for a simpler answer?

 

[91explorer1009]

Haha, no you are correct, I did. I isolated it, but I am still trying to find out what the third controls...I am trying to isolate the last one? Thanks

 

[arco777]

Everything I can find says the relays under the power dist box are A/C cutoff, fuel pump, and EEC power.

Well, then I wanted to know where the blower relay is on a 91. It's in the main box on a 93-94. It shows in the electrical diagrams I have for 93-94 as well.

I have been googling the crap out of this issue for the past while.

It would seem that on a 91 and maybe also on a 92, there is NO blower relay - the current is run through the switch (through the resistor coils of course).

Check this link below out. The tech initially suggests a failed relay as cause for an inop blower motor. When he posts a wiring diagram, note there is NO relay in that circuit! This is different from a 93/94 circuit.
http://www.justanswer.com/ford/15591-1991-ford-explorer-xl-4-0-engine-standard.html

Everywhere I search, there's no mention of a blower relay on a 91 Explorer.

 

[arco777]

Relating to your initial problem, that leaves two possible culprits. My money is on the switch being bad. There has to be a reason that the relay was added in future revisions. You don't put that much current through a simple switch and expect it to last; I bet your switch needs cleaned or replaced.

That of course assumes that the wiring is all intact. Check your connections; I have seen the main blower fan connector heat up and partially melt, making a loose connection internally.

Resistor coils do go bad, but they are pretty much just good or bad. You'd notice the fan wouldn't work at all, or it would only work on certain speeds. Not on and off. The coils and connector are mounted on the heater box and are pretty easy to access.

 

[91explorer1009]

thanks so much for trying, thats basically what I had found from all my searching. Some answers were saying there is no relay and some say there is. If anyone else could chime in whos experienced this before would help. thats why I came to the forum, searching has left me confused. I guess if there is no relay to replalce I will just replace the blower motor...didnt want to do that but oh well..

 

[arco777]

thanks so much for trying, thats basically what I had found from all my searching. Some answers were saying there is no relay and some say there is. If anyone else could chime in whos experienced this before would help. thats why I came to the forum, searching has left me confused. I guess if there is no relay to replalce I will just replace the blower motor...didnt want to do that but oh well..

I just checked the wiring diagram for a 91 Explorer here and it shows no relay again, so I think it's confirmed. - http://www.autozone.com/autozone/repairinfo/repairguide/repaiguideOverlay.jsp?src=http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0996b43f/80/21/19/62/large/0996b43f80211962.&imageType=gif&imageName=Fig.%208:%201991%20Explorer%20body%20wiring

Before replacing the blower motor, test it - you say it works intermittently? Try taking it out and holding it in your hand, with it plugged in. Have someone turn it on at the switch. It should spin up; shake it and see if it keeps running or stutters. If it won't spin at all when it's turned on, rotate it a bit by hand and see if it starts going. Either way it would indicate internal damage to the blower motor.

Also, when the blower motor isn't running with the switch on, probe the connector going to it with a multimeter and see if you have voltage. If you have voltage the motor may be to fault - but if you plug in the motor and the voltage drops, it may be either an internal short in the motor (unlikely) or rather the worn out switch can't handle the amp draw of the motor.

 

[91explorer1009]

thanks for all the help arco....seems you are the only one whos chiming in. I will try this in the morning, thanks

 

[malohnes]

Hi, I have had this problem not long ago on my 91. Found out it was the connector going to the switch. Wiggle test made it come on and off. Cleaned the contacts and made sure there was no freying of wires and all is well again.

 

[91explorer1009]

i cleaned the connectors and even put some dielectric grease on the contacts, still doing it, a bit though...how could I clean/change the contacts or connector without replacing everything?

 

[arco777]

i cleaned the connectors and even put some dielectric grease on the contacts, still doing it, a bit though...how could I clean/change the contacts or connector without replacing everything?

If the contacts are loose, you can often release the female connector terminals from the connector body - usually all it will take is a small pick or x-acto knife to lift up the locking tab and slide the terminal out. Once out, you can bend the terminal contact points so they grab the male terminal tigher.

For mechanical slide contacts, like rotary switches (fan switch), you can take the switch mechanism apart and get at the internal assembly. If you do it carefully you'll be able to put it together again - otherwise any parts under spring tension might fly out and get lost. Contact points that slide against each other or even points like in a window switch can be cleaned with sandpaper. They get corroded and pitted over time, making a bad connection.

 

[91explorer1009]

thanks, I will try it when it stops raining...