dkarten

2 vehicles with same problem, 1990 100Q & 1987 5KQ, '90 100 AC works, 1st sp. fan does not come on with AC or when after run sensor wires are crossed, replaced "timer relay" #3,(after run relay?) no change, '87 5K AC not charged, 1st sp fan does not come on when after run sensor wires are crossed, both have new Rad Thermo switches, both Rad fans #2 & 3 come on properly, '87 5K seems to have no after run relay in fuse box, should I check after run relay under dash in both cars? Resistor pack on '87 5K is new, 100 resistor pack looks OK

shortyq

1st speed is controlled by a relay in the fuse block. It is looking for ground through either the AC switch or afterrun. Try jumping that relay first. "Radiator Fan Position 1" in the deck. If no, bad resistor pack or wiring. If yes, replace relay with known good.

Scott J

dkarten

I do not see which relay in the fuse box is after run relay in 1987 5K, SJM says #6 is relay on Turbo models but in non turbo #6 is not used

audiqv8

Non turbo does not have an after run relay to control the radiator fan and pump. The after run radiator fan and pump is only used in Turbo model. Check the radiator fan resistor.

shortyq

If you take a jumper wire across the low speed fan relay, the low speed fan should run (it takes all the inputs to the fan operation and makes them not a factor). If no, you need to go downstream = wiring to/from and/or resistor pack. The resistor pack controls low speed fan and medium speed fan. High speed fan is a direct connect to 12v. If the fan does work (If yes), then it's the inputs upstream of the fan relay.

I did have a couple type 44 cars years ago that had a broken trigger wire to the low speed fan relay under the dash. Again, your first step is to determine if you are upstream or downstream of the relay.

HTH
Scott J

dkarten

Rad fan resistor in 100 checks OK

dkarten

OK, I'll jumper the low speed relay in 100 & report back, what can I check on 5K?

shortyq

The fan operation works the same way in the 5k

audimafiaoso

<center><img src="http://pictureposter.audiworld.com/108185/etka.jpg"></center><p>
There is a sensor mounted on the back of the valve cover.

This sensor starts the fan in first speed mode from the build up of ambient heat..


The sensor is #13 in the ill. mounted to #12

Jump the two wires to this sensor and see if your fan will operate..

I have the same year and model 87 Q 5000 nonturbo as you do..


Hope this helps..

You do need the 'after run relay' it's located under the drivers side map shelf...

Pos #18 part # 443-955-532C was superseded from 443-955-532A Top right on the 87 Q

dkarten

I have tried wires at sensor, no change, &amp; now suspect relay under dash, 1990 100Q has same problem, I tried jumpering terminals at relay #3 in fuse box, no change, but not sure of which terminals to jump, 1 position seemed to short out &amp; I saw smoke from under fuse box, can anyone tell me which terminals to jump at relay in 1990 100