Horn and Cruise Contol Not Working - Wiring Harness?

[nvestysly]

I had originally added comments to another thread:

http://www.b190.com/viewtopic.php?f=4&t=506

But now I've decided to make a new thread since my issues seem to be different than the original thread.

A month or so ago I realized the horn and cruise control were not working. This 1998 van was purchased "used as-is" recently from a private buyer and of the many things we checked when purchasing the van, horn and cruise control were not on the list. Even if we had... I don't know if we would have realized the implications. I don't know the last time the horn and cruise control worked.

By the way, there is no indication the steering wheel airbag is not working. In addition, a Ford technician checked to see if the computer stored any error codes and they did not see any problems registered.

I checked the clockspring on the van and everything seems to be in order meaning I checked the continuity of mechanism and all the pins checked okay. I get continuity from the connectors in the steering wheel to the connectors at the base of the steering column However, that is about my limit of troubleshooting. I don't have the shop manuals for this vehicle so I don't know what to check next.

The Ford technician indicated he checked the fuse box in the engine compartment (above the ABS valve module on the driver side) and found no power to the horn and cruise control circuit. His first reaction was replace the engine compartment wiring harness but later found it is not available from Ford or from LKQ.com (salvage yard). So the technician suggested I leave the van with them so they can do more troubleshooting and find the problem. This sounds good but they want me to tell them how much time to spend (at $120 per hour) before I cry "ouch!" I'd be willing to spend 2 or 3 hours if I felt confident the problem would be resolved. Argghh! I realize this type of problem is not straightforward but I'm not sure I want to spend large sums of money on this problem.

I need the horn for safety reasons. I can get by without cruise control.

Here are some options as I see them. Your comments are appreciated.

1) Go without a horn. Lot's of people probably drive cars with inoperable horns. However, this makes me feel uncomfortable as I recently avoided a crash by alerting the offending driver with a toot of my horn (different vehicle).

2) Allow the Ford technician to do some troubleshooting. If so, how many hours (at $120/hour) would you be willing to pay?

3) Rewire the horn the old-fashioned way. I'll buy a separate relay, hook it up to the positive side of the battery, hook up the ground (the mounting tab of the relay), hook up the horn and attach the other leg to the wire coming from the horn button. A little crude... but at least I get a working horn. Total cost probably less than $50 and several hours of my time. Here's a link to a sample diagram I found:

http://www.theautomotiveindia.com/forum ... relay.html

[nvestysly]

I'm working on the van this morning and I'm leaning toward some version of item 3 above.

Going without a horn (item 1 above) is really not a good option since I feel it's a safety issue and my wife, it's her sister who will be driving the van soon, definitely wants a working horn.

Paying somebody to troubleshoot (item 2) is a possibility and I haven't excluded that option yet. Just want to see what I can do first.

There is no power to the horn relay under the hood. Two of the legs of the horn relay are supposed to have power at all times. The circuit diagram I found online indicates there is an in-line fuse but I can't find it. I may not fully understand the diagram I found online and there is always a chance the information I found is for a slightly different vehicle. Regardless, I was able to make a temporary set of jumper wires to get the horn working this morning. I removed the horn relay from the terminal box under the hood and then connected 12V to the two legs of the relay, then jumped the other legs of the relay back to the terminal box. Presto the horn works! Now I just have to find a more permanent solution. I also need to drive the vehicle and see if the cruise control is magically working now since the horn relay feeds other items in the steering wheel in addition to the horn.

For reference, the diagram I found is in post # 5 on the following link:

http://www.ford-trucks.com/forums/69874 ... moval.html

The person who made the post in the link above accidentally posted the diagram for an Econoline (just what I needed) rather than a Ford F series truck. My good fortune that they made a mistake.

Test drive this afternoon and I'll report back.

on edit: does anyone have shop manuals including wiring diagrams for a 1998 E350?

Lucius

[nvestysly]

I drove the van after lunch and both the horn and cruise control are working with my temporary fix.

At this point I'm not prepared to make the full repair. I'm not even sure what the full repair would be except to say it would involve diagnosing the wiring harness and power junction box to understand why power is not present at the relay pins.

So for now I'm taking the approach of a reasonable short-term fix that may keep working forever. I'm going to make a jumper to get 12V to the relay and make a jumper from the relay to the junction box. I'll make sure all the connections are insulated and I'll put a 15A fuse in the 12V line. This will be a "flying leads" jumper - a pseudo wire harness to allow the relay to hang (via the homemade wire harness) outside the junction box.

Referring to the diagram I will make a jumper from the horn relay to the YE/LG wire (pin/socket 6), I'll make another jumper from the horn relay to the DB wire (pin/socket 1), then I'll attach the 15A fused wire to the YE/LG wire (pin/socket 460). I cannot actually see the wire colors because the sockets are embedded into the junction box but the layout of the relay will look familiar if you take yours out and look at the blades. Note that if you remove the relay and look at the schematic on the side of the relay cube the contacts have different numbers but you can look at the schematic on the cube and compare it to the diagram to see which contacts correspond to which.

Clear as mud right?

If I can take a picture of my final arrangement I'll post it here.

On a related note, I joined the Ford Truck Enthusiasts forum http://www.ford-trucks.com so I can learn more about the E350 side of the B190. They have a subforum for vans and there are many threads from people experiencing trouble with their horn and cruise control.

[Keystone]

Congratulations on your diagnosis and temporary/semi-permanent solution! I feel certain you made the right choice, as even having the root cause properly identified doesn't mean that the fix will be easy or cheap. Similar to this problem, in my '99 Tacoma, the wiring harness is pinched--somewhere--causing the ABS sensors to read bad. It's a common issue, yet owners are frequently convinced by dealers to spend $$$ replacing sensors that don't fix the problem, and then finally replace crazy expensive harnesses.

Sometimes the right thing to do is a brute-force fix. In my case, that fix was to disconnect the ABS so it doesn't come on randomly (and ABS was an option anyway), or in your case, the fix was to wire around the harness to the horn (as you have done, for a non-optional feature).

Great sleuthing, great story--I'm saving this in my "it could happen to me" file...

[nvestysly]

I found this picture on ford-trucks.com. The arrow points to the horn relay. As I said in the earlier post, I removed the relay and made a jumper to power the relay. All is good for now.

I'm amazed at how many people in vans and trucks seem to have some sort of problem with the horn and cruise control. There are a variety of root causes and very few seem to have the problem I had - no power to the relay. I'm going to check Technical Service Bulletins and recall notices - with this many issues it seems like there are systemic defects.

[nvestysly]

I was not able to identify any technical service bulletins or recalls associated with horn and cruise control problems. However, other than performing internet searches I don't have a means to find this kind of information. That is, I don't have a membership to a technical service that provides this type of information.

The local Ford dealer contacted me to ask if I was returning to have their technician perform additional troubleshooting. I told him I had come up with a workable solution on my own. He said no problem - there would be no charge for the work they had done earlier in the week. All he asked was that I give them some business in the future.

[lido14co]

Great posts! Best thing about this site is the sharing of solutions. Thanks!


Cliff