Resolved Windshield wiper troubleshooting - Wiper turns OFF when Headlights turned ON

[afjLX]

Ok, on to the next issue on my 1987 fox and starting this thread for help. The windshield wipers come on but shut off when the headlights are turned on. Bad news is this 1987 was a 4cyl to 5.0 swap. So wiring could be the culprit. Posting here to see if anyone has seen this issue before in general? I'm about to start digging through the 1987 EVTM.

Some things I had questions on and things to note:

1. Just using the headlights by themselves -> whenever I turn the headlights OFF, a chime rings is that normal? When this chime rings after turning OFF the headlights, the warning indicators on the bottom right (1987 cluster) all come on - I'm guessing this not normal
2. Wipers come on but speed adjustment on stalk doesn't do anything. Turning on the headlights stops the wiper even if the wiper switch is on.
3. The Multifunction switch appears to be new. Anyone hear of the wrong MFS causing this issue?

I'm leaning towards the MFS being an issue or wiring there as an issue. Thoughts?

*UPDATE FIX*

Well finally was able to dedicate some time to this. Found the issue was a bad ground at wipe wiper motor. Ran a separate ground to the the shock tower and all is well now. All speeds work.

 

[General karthief]

Pull the MFS and look for a part number

 

[afjLX]

Pull the MFS and look for a part number

Good idea. Hopefully there is a PN stamped on it somewhere.

 

[89notchDude]

Interesting bc I have an 89 4 cyl to 5.0 car and my wipers and chime dont work and once the key is in the run position, the front parking lights are always on no matter if the switch is on or off. I installed a new headlight switch and turn signal switch. Something is crossed. I will be following this thread.

 

[afjLX]

Ok, on to the next issue on my 1987 fox and starting this thread for help. The windshield wipers come on but shut off when the headlights are turned on. Bad news is this 1987 was a 4cyl to 5.0 swap. So wiring could be the culprit. Posting here to see if anyone has seen this issue before in general? I'm about to start digging through the 1987 EVTM.

Some things I had questions on and things to note:

1. Just using the headlights by themselves -> whenever I turn the headlights OFF, a chime rings is that normal? When this chime rings after turning OFF the headlights, the warning indicators on the bottom right (1987 cluster) all come on - I'm guessing this not normal
2. Wipers come on but speed adjustment on stalk doesn't do anything. Turning on the headlights stops the wiper even if the wiper switch is on.
3. The Multifunction switch appears to be new. Anyone hear of the wrong MFS causing this issue?

I'm leaning towards the MFS being an issue or wiring there as an issue. Thoughts?

Well finally was able to dedicate some time to this. Found the issue was a bad ground at wipe wiper motor. Ran a separate ground to the the shock tower and all is well now. All speeds work.

 

[General karthief]

All is well with a random wire hang'n out under the hood..... I hate to see that, looked into tracing the proper ground wire for the issud?

 

[afjLX]

All is well with a random wire hang'n out under the hood..... I hate to see that, looked into tracing the proper ground wire for the issud?

It’s hard to see. It’s black and a very short run under the bundle that goes into the firewall. Looks factory. The only thing that bothers me is the yellow eyelit crimp I used. But I mounted at the back where it is not visible.

 

[Noobz347]

*UPDATE FIX*

Well finally was able to dedicate some time to this. Found the issue was a bad ground at wipe wiper motor. Ran a separate ground to the the shock tower and all is well now. All speeds work.

Rookie

That's what [Resolved] buttons and last posts are for.

 

[afjLX]

Rookie

That's what [Resolved] buttons and last posts are for.

lol I had no idea. I selected resolved

 

[Noobz347]

lol I had no idea. I selected resolved

You un-resolved it again.

I in-turn re-resolved it.

Glad we got [that] resolved.

 

[General karthief]

Now I'm REALLY confused
I know , what's new?