Hello All, Does anyone out there have a wiring diagram for a 1994 Suzuki DD51T. Specifically the 4WD system. Trying to track down why my 4WD, axle and diff lock lights don't come on and not locking.
There’s a silver box screwed (4wd controller) to the front firewall behind the clutch pedal way up high that activates the axle lock and diff lock , royal PITA to get to and not cheap to replace . Come across a few bad ones , been rebuilding them , I’ll look around as I got the pin out of the box and switches written down plus a wiring diagram too Try to post soon
Thanks for the reply. I have the controller out and yes a royal PITA to find and remove. Not much room to twist around. A pin out diagram would help a lot. Since the mini relays are good what parts have you replaced inside controller that gives a signal to the relays? Or anything you think it might be. I'm sure it's doable.
I’ve been gutting them and installing self latching relay boards , it’s easier then trying to find all the parts and it seems the control chip craps out and it’s too much a PITA to find ( not been able to ) I’ve done a few with just adding toggle switch’s too but doesn’t look as clean The stock controller has a lot of safety/over complicated checks and balances built in that just adds to more links in the chain to brake
SGMBilly & Koffer, Brand new member, new (to me) DD51T & first post. Inoperative 4X4 Controller and possible fix I am chiming in as the 4X4 Controller on the vehicle I purchased wasn't functioning (caught on pre purchase inspection) and I read this post - after discovery and before purchase. The push buttons on the axle lock and diff lock were having no affect on front wheel engagement - no orange lights no 4wd dash light - nor was rear diff locking & no diff lock orange light and/or axle lock orange light. Dealer (large importer of these things) realized that this was a deal breaker for me. Dealer's mechanic was very familiar with the oft malfunctioning (and now discontinued) 4X4 controllers and had devised a "hot wired" solution with a 15 amp fused lead to both the Front axle VSV via toggle switch as well as the rear diff VSV (two independent switches from one fused hot lead) - put the toggle switches in the two adjacent blank off plates next to the stock axle lock and diff lock push button (these were left connected) . Fused 12 V hot lead from fuse block - through simple toggle (on or off) then directly to activation electrical lead at respective VSV via a tie in (energized the circuit). Here is the mechanical action and light show - ( I elevated all four wheels with jacks/stands - had a helper start the vehicle and engage). Lever select 2 High - No lights - rear drive only - no diff lock mechanical - open rear diff. (validated by locking one rear wheel mechanically) - no diff lock light- functions as designed Lever select 4 High or 4 Low - rear drive and wheels same as above - plus forward drive shaft engaged but front wheels are not engaged - no lights Lever select 4 High or 4 Low - energize forward axle VSV via the toggle - same as as above except now the front wheels are engaged (spin - open differential) - get 4WD green light in dash & axle Lock orange light in OEM push button switch. Now vehicle is functioning as designed in 4WD - drive to all 4 wheels via open differentials. Flip axle lock toggle off - front wheels disengage orange light in axle lock extinguishes. Diff Lock Toggle - If Diff Lock toggle is energized - it energizes the rear diff VSV. The orange light in the OEM Diff Lock switch will illuminate and it will mechanically lock rear differential - validated that both rear wheels spin at same rpm despite differing resistance on wheels. In this configuration it makes no difference what position the lever selector is in 2 High, 4 High, or 4 Low. I believe that this feature is not OEM (the ability to lock rear diff in 2 High). Now, I am very cautious about this setup (the ability to directly energize the respective VSV's directly without going through the controller - no safety interlocks). I am careful to have everything stopped before engaging the toggles (on or off). My plan is to remove the 4X4 controller - open it up if able, clean with electrical contact cleaner, clean grounds and reinstall, pull fuse on dealer mechanics hotwire, and see if I can reestablish OEM configuration. If successful, great, if not, I plan to replace the open toggles with guarded switch toggles (prevents inadvertent activation & "hopefully" makes you think before flipping the switch(s) @ 70 KMH) and continue to use the vehicle in current configuration with the operator being the only safety interlock & hope my differentials doesn't get smoke checked.
My 4wd controller went to Hades. The circuit board on the controller burnt something out. I have read something on another post that had pics and a wiring diagram of the front diff. There are 2 solenoids on the front diff. I brought power from the yellow wire on the connector for the 4wd controller to a flush mount toggle switch, with a red led light, and ran it to the front diff. From there, I spliced the 12vdc and the ground to the wires on the 2 solenoids at the front diff. When the switch is turned on, the 4wd light in the dash turns on and the front axle engages. I hope this will help someone out. These controllers are hard to find. Don't make the mistakes I made and wire the switch to the transfer case and the same looking switch on the front diff. These are switches that turn the indicator lights on and will blow a fuse. The solenoids on the front diff are side by side. They should be turned on at the same time.
