Diff ECU Relay chattering

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haligen

haligen

10 Year
Joined
Nov 1, 2011
Threads
13
Messages
110
Location
Conway, SC
I'm going to pull the diff ecu here in a little while to check for corrosion but I had a question as to whether the relays should be trying to engage just driving down the road. I bought the truck with a weird chattering noise coming from the drivers kickpanel. It only happened once in a while and would randomly come and go. Its a bit annoying but everything worked as it should (center locked and diffs could be engaged). Now I get the blinking lights. I'm wondering if the the diff ecu relays have finally kicked the bucket and the two problems are related. The vehicle is a 93 with factory lockers.
 
Check the wiring harness, they may be shorting and trying to engage the diffs.
 
If it where shorting at all it should blow a fuse. maybe you can try a very low amp breaker and see if it trips just driving.
 
scrowley said:
If it where shorting at all it should blow a fuse. maybe you can try a very low amp breaker and see if it trips just driving.
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Depends on what is shorting, how it is shorting, and how long it's shorting for.

A fuse won't blow if it is shorting in a manner that mimics what it's supposed to do.
 
jonheld said:
There are several relays in the driver's kick panel. Maybe you should identify which one is making noise and go from there.
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I had already pulled the panel before posting and sitting in the driveway I can put my hand on the diff ecu and feel the chattering. Looked at the immediate connections and they looked fine. Guess I'll do some more investigation tomorrow when it's light out.
 
haligen said:
I had already pulled the panel before posting and sitting in the driveway I can put my hand on the diff ecu and feel the chattering. Looked at the immediate connections and they looked fine. Guess I'll do some more investigation tomorrow when it's light out.
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I'd start with the harnesses to the axle and t-case. Also check the connections themselves, if they aren't properly sealed water can get in and cause corrosion. I'd pull it all apart, clean it, and use a bunch of dielectric grease to seal it up nice and tight.
 
I may have a spare diff ECU if you need one. Shoot me a pm if you want it.
Louis
 
I didn't realize there were two, but yeah it's the one in the US drivers kick panel.
 
Well I pulled the relay box and tested it per some instructions found in another thread. I didn't have a 9v battery so I used a DC regulated power supply set for 9v 1.5a. The relay box checked out so under the truck I went. When I pulled the connections on the diff lock switch and the 4wd switch connections both looked burned. I jumpered the diff indicator harness with a paper clip and the light came on. I jumpered the 4wd hardness and the actuator didn't move. Pulled the motor harness and tried the pin 2 pin 3 flip flop with nothing moving. Then I looked at the motor harness. I'm going to take a shot in the dark but I think it might be the culprit. Guess out comes the motor tomorrow.
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haligen said:
I jumpered the diff indicator harness with a paper clip and the light came on.
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Which one are the ones that activate the dash light .?

After my manual tranny swap I don't have 4WD dash light when my front DS it's engaged .. and need to dedicate time to solve that ..
 
Tapage said:
Which one are the ones that activate the dash light .?

After my manual tranny swap I don't have 4WD dash light when my front DS it's engaged .. and need to dedicate time to solve that ..
Click to expand...

Closest one to the front.
 
Well a nice mudder was kind enough to sell me a relay box. Just came in today but as I figured it didn't solve the problem. Oh well nice to have spares and I guess it's time to pull that actuator.
 
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