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Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 5589
Experience:  Owner at DJ Wilson
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Cruise/Wipers/Air horn not working

Customer Question

Dan, I have an '09 Prostar. Cruise/Wipers/Air horn all go out at the same time. Just left the shop for and abs diagnostics where they had the whole dash open, now AC isn't working either. Wondering if some fuses were jacked when replacing the panel. Already 3 times at an electrical shop for the cruise/wiper problem and can't keep them functioning. Any suggestions?

Submitted: 2 years ago.
Category: Medium and Heavy Trucks
Expert:  Daniel Wilson replied 2 years ago.
Hi Customer, Thanks for the request. I was not logged in when you posted your question but I will be glad to help if you still need help with this. Let me know the last 8 of your VIN. Also did this probem occur right after the dash work or was this the reason they were in the dash? Are you able to pull body controller fault codes through the display in the dash? If so let me know what you have for codes.Sounds like a potential harness problem( short/open circuit or controller problem. Let me know
Customer: replied 2 years ago.


VIN is R29C049638. Here's the story:

We've been having intermittent problems linked to the electrical. The cruise, wipers and air horn would go out every time you would plug something into the lighter. Three trips to the electrician for that. During that time frame, the ABS reported a short and trac light came on dash. Then we had a low voltage problem. After replacing the alternator, voltage problem still appeared. Took it to the dealer for the voltage and it ended up all the battery cables were loose and toasted. Since it was there we had them check the ABS. They diagnosed along with Bendix and swapped ECM and Yaw sensor with know good one and nothing. Bendix ended up saying it was going to be a short in the wiring somewhere. When we picked up the truck, AC stopped working and wipers/cruise etc as well. Last night I opened up the fuse box and noticed several wires cut due to the ties being too tight. I removed all the ties and taped up all the cuts etc. Once loose, AC kicked on, wipers kicked on etc. I'm trying to pin point it but I cant find the fuse leading to the wiper issues. In that, I found one fuse, dont remember which it was right now, that doesn't have a ground in the socket, just one prong, which I found very odd as that doesnt seem to complete a circuit.

I'll find out which fuse that was. I'm hoping you know where I could start with these errors. As far as the ABS, there was a line cut on the front passenger side that we repaired, but the light is still on. I can't remember the code right now for the body controller but it was something like 3687 Body Controller; with no message. Again, I'll get that exact info this afternoon.

Thanks for your reply


Expert:  Daniel Wilson replied 2 years ago.
Hi Isaac, Thanks for the update. First I would go back to the area of the harness that was taped up. Repair the damaged wiring in that area as there could be still problems there and some loose connections causing your loss of functions. Try a wiggle test in that area to see if the functions come back. Also clean and inspect all your grounds as well. LEt me know
Customer: replied 2 years ago.

Ok. Seems as if removing the ties helped alleviate some of the strain and get those functions working. Still don't know the exact culprit. I'll try cleaning up that damage line by line. I'll probably go fuse by fuse and see which one kicks those wipers off. Should have started there first I guess.

The ABS line; I'm gonna try soldering the lines together, see if that takes. Before actually going wire by wire. I got the codes from the dash:

1808 Antilock Brakes

3987:5 Body Controller

520906:13 Body Controller

639: Headway

Any ideas?


Ok. Got more ABS info. Completely replaced the sensor that was split. Afterwards, the dash gave full info of faults:

639 Headway- J1939 Engine communications and J1939 Datalink

1238:2 Body Controller- Faulty switch actuator or microswitch for ATC off-road switch

3987: 5 Compression brake indicator output is under current.

Expert:  Daniel Wilson replied 2 years ago.
Hi Isaac. I believe you are going to find that this is all harness related most likely. If wiggling the harness causes these functions to come back it means you have shorted or broken wiring or loos or corroded connections in the connector pins. Start repairing any chafed wires and heat shrink the connections and also check all the connector pins for loose pins and corrosion and repair as necessary.